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CHAPTER 5
Sample Request
for Proposals Template
5.1 Introduction
This RFP presents sample language for household travel surveys that are based on the recom-
mended standardized procedures and guidance in this report (see Chapter 2). Intentionally, the
language is prescriptive, as it would be in an RFP. It should not be misinterpreted as advocating
that this is how travel surveys must be done. Footnotes are provided that reference the relevant
sections of Chapter 2. Where an agency-specific number or value is required (e.g., number of
presentations to management), a blank is shown in which each agency should substitute its
desired value or number.
To make it easier to use the material in this chapter in preparing an actual RFP, the table and
equation numbering are restarted at 1. Note that this template is intended to address only the
Scope of Work section of an RFP. There are other documents that include complete RFPs,
notably Travel Survey Manual published by the Transportation Model Improvement Program
(TMIP, 1996b).
5.2 Request for Proposals
5.2.1 Scope of Work
This section defines the minimum scope of work to be accomplished by the Survey Contractor.
It is presented in this RFP in two subsections: Task Plan and Schedule.
Task Plan
Task 1: Project Work Program and Management Plan
Within ____________ days of contract execution, the Contractor will meet with Agency staff
to initiate the project, discuss the work plan and schedule, and define project management roles
and responsibilities. The outcome of this meeting is a revised work program and project man-
agement plan as initial deliverables.
The Agency internal project management staff includes
· ____________, with overall project management responsibility;
· ____________, responsible for day-to-day project coordination; and,
· ____________, responsible for on-going data quality assurance.
The Contractor will be expected to
· Designate a Project Manager who will serve as the single point of contact for all survey issues;
· Make ____________ presentations to Agency staff regarding survey progress and issues;
· Make presentations to and attend ____________ meetings of the Study Steering Committee;
68
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Sample Request for Proposals Template 69
· Make a presentation of survey results to Agency management and staff;
· Prepare drafts of press releases regarding the survey effort for review and dissemination by
Agency staff; and,
· Attend other meetings on an occasional basis as requested by the Agency Project Manager.
Task 2: Develop Survey Sampling Plan
The Contractor will prepare a survey sampling plan for review and discussion with Agency
staff and the Steering Committee. The proposal should include a preliminary definition of the
sampling plan and a discussion of
· Definition of the sampling frame for the main household travel survey;
· The number of households to be sampled, and the expected number of completed surveys,
by cell of the main survey sampling frame;
· Need for augment samples (households that are recruited specifically for certain charac-
teristics that are relatively rare in the local general population). These could include
Households using specific transit modes (e.g., local bus, express bus, rail, ferry, or bicycle);
Households using specific road facilities (e.g., certain highways, toll roads, or HOV lanes);
Households using park-and-ride to a transit mode; and/or
Households that represent other special population groups.
· Time dimensions of samples, including a discussion of
24-, 48-, or other hour period for main sample;
Weekdays only (all days or only a subset);
Weekend sub-sample (Saturday/Sunday only, or as 48-hour pairs, such as Friday/Saturday
and Sunday/Monday pairs); and
Summer sub-sample.
The Contractor shall use the following guidelines in drawing a sample1:
1. To overcome unanticipated sample loss (refusals, etc.), a large random sample should be
drawn. The sample size should be based on the expected non-response rate (which may be
determined during the pretest).
2. When a telephone sample is used, the order in which telephone numbers are drawn must
be preserved. For example, for a Random Digit Dialing (RDD) list, numbers generated later
in the list must not be recruited before numbers listed earlier in the list.
3. If using RAND Corporation (1955) random numbers, additional sample may be created
and drawn after the initial sample has been exhausted. If using RDD lists, this must not be
done because the two random samples will not be related.
4. Refusal conversion should be conducted, with a maximum of five call attempts to convert
an initial soft refusal (therefore six calls to the household, in total).
Task 3: Survey Instruments and Data Collection Procedures
Survey Questions Data elements that must be included in the survey are shown in Table 1.2 It
is further expected that the Contractor shall use the response categories shown in Table 23 and the
standard question wordings shown in Table 3.4 With respect to Table 2, at least the primary cate-
gories must be used. However, discussion with the agency should occur to determine whether any
secondary categories must be used.
1
Sample Replacement, Section 2.2.4
2
Minimum Question Specification, Section 2.1.1
3
Standardization of Categories, Section 2.1.2
4
Standard Question Wordings, Section 2.1.3
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70 Standardized Procedures for Personal Travel Surveys
Table 1. Minimum questions.a
Category Item Description
Household Location Home address or home position in geographic terms
Type of Building Detached, semi-detached, terraced, flat, etc.
Household Size Number of household members
Relationships Matrix of relationships between all members of the household
Number of Vehicles Summary of number of vehicles from vehicle data
Housing Tenure Own or rent status
Re-contact Willingness to be contacted again for further surveys, etc.
Personal Gender
Year of Birth (Preferable to requesting age)
Paid Jobs Number of paid positions and hours worked at each in the past week
Job Classification Employee, self-employed, student, unemployed, retired, not employed, etc.
Driving License Whether a current driver's license is held
Non-mobility Indication of why no out-of-home activity was performed on a survey day
including work-at-home days
Education Level Highest level of education achieved
Handicap Types of mobility handicap, both temporary and permanent
Raceb Defined as currently measured in the U.S. Census
Vehicle Body Type For example, car, van, RV, SUV, etc.
Year of Production
Ownership of Vehicle Household/person, lease, institution
Use of Vehicle Main user of vehicle
Activity Start Timec
Activity or Purpose
Location Where the activity was performed, unless traveling
Means of Travel If activity is travel, what mode(s) was used (including specifying if a car
passenger or driver)
Mode Sequence Unless collected as fully segmented data
Group Size Number of persons traveling with respondent as a group
Group Membership Number of persons in the group who live in respondent's household
Costs Total amount spent on tolls, fares and respondent's share
Parking Amount spent to park
a
Minimum Question Specification, Section 2.1.1.
b
All surveys shall use the U.S. Census Bureau definition of Race.
c
Only start time needs to be ascertained in a time-use or activity survey because, by definition, the start time of an activity is
the end time of the previous activity. Only the last activity should need an end time. In a trip-based survey, start and end time
should be included.
The Contractor shall include a question to verify reported non-mobility to be asked of all per-
sons who report they did not travel (stayed in one place/did not leave home) during the entire travel
period.5 It is strongly preferred that the Contractor also include questions that gently challenge per-
sons who report non-mobility by asking for the reason(s) why no travel was made during that day.
Survey Instruments The Contractor will provide a schedule of contacts and reminders for the
data collection process, specifying the type of contact to be used in each step. Contractors shall
include as a minimum Steps 1 through 6 from Table 4, although it is desired that Contractors
employ all 11 steps,6 unless it can be shown that later steps are no longer cost-effective.
For mailed materials, the Contractor shall use the following with regard to the format and
appearance of the materials:7
· For any materials to be returned via mail, the respondent must be provided with a stamped
return envelope, preferably with instructions as to which materials should be mailed back
(if any);
5
Incorrect Reporting of Non-Mobility, Section 2.4.6
6
Number and Type of Contacts, Section 2.2.1
7
Mailing Materials, Section 2.4.2
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Sample Request for Proposals Template 71
Table 2. Response categories.a
Variable Primary Category Code Secondary Category Code
Type of Dwelling Single-family house detached 1 Single-family house detached 10
(H2) Single-family house attached 2 Townhouse 21
Row house 22
Duplex 23
Triplex/fourplex 24
Apartment/mother-in-law suite 25
Apartment/condominium 3 Condominium 31
Rented apartment 32
Mobile home/trailer 4 Mobile home 41
Trailer/camper 42
Dorm/group quarters 5 Dormitory 51
Hostel 52
Nursing home 53
Military barracks 54
Hotel/motel 6 Hotel/motel 60
Other 9 Other 90
Relationship (H4) Self 1 Self 10
Spouse/partner 2 Husband/wife 21
De facto husband/de facto wife 22
Son/daughter 3 Natural son/daughter 31
Adopted son/daughter 32
Stepson/stepdaughter 33
Son-in-law/daughter-in-law 34
Father/mother 4 Natural father/mother 41
Adopted father/mother 42
Stepfather/stepmother 43
Father-in-law/mother-in-law 44
Brother/sister 5 Natural brother/sister 51
Adopted brother/sister 52
Stepbrother/stepsister 53
Brother-in-law/sister-in-law 54
Grandfather/grandmother 6 Paternal grandfather/grandmother 61
Maternal grandfather/grandmother 62
Grandchild 7 Grandson 71
Granddaughter 72
Other relative 8 Male 81
Female 82
Not related 9 Boarder 91
Housemate/ room mate 92
Other non-relative 93
Housing Tenure Own 1 Owned with mortgage 11
(H7) Owned without mortgage 12
Rent 2 Rent paid 21
Occupied without rent 22
Provided by job/military 3 Provided by job 31
Provided by military 32
Education Level No school completed 1 No school completed 10
(P10) Elementary school 2 Preschool/nursery 21
Kindergarten4th grade 22
High school 3 5th8th grade (junior high) 31
9th12th grade (no diploma) 32
High school diploma 33
College/university 4 Some college but no degree 41
Associate degree in college 42
Bachelor's degree 43
Post-graduate studies 5 Some graduate school, no degree 51
Master's degree 52
Professional school degree 53
Doctorate degree 54
Disability (P11) Difficulty standing 1 Difficulty standing 10
Difficulty climbing 2 Difficulty climbing 20
Visually impaired/blind 3 Visually impaired/blind 30
Hearing impaired/deaf 4 Hearing impaired/deaf 40
Require wheelchair 5 Require wheelchair 50
Require cane/walker 6 Require cane/walker 60
Other (specify) 9 Other (specify) 90
(continued on next page)
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72 Standardized Procedures for Personal Travel Surveys
Table 2. (Continued).
Variable Primary Category Code Secondary Category Code
Race (P12) White (alone) 1 White (alone) 10
Black/African American (alone) 2 Black/African American (alone) 20
American Indian/Alaskan Native 3 American Indian 31
(alone) Alaskan Native 32
Asian (alone) 4 Asian Indian 41
Chinese 42
Filipino 43
Japanese 44
Korean 45
Vietnamese 46
Other Asian 47
Native Hawaiian or Pacific Islander 5 Native Hawaiian 51
(alone) Guamanian or Chamorro 52
Samoan 53
Other Pacific Islander 54
Some other race (alone) 6 Some other race (alone) 60
Two or more races 7 Two or more races 70
Vehicle Body Type Auto 1 Auto 10
(V1) Van 2 Van 20
Recreational vehicle (RV) 3 Recreational vehicle (RV) 30
Utility vehicle 4 Utility vehicle 40
Pick-up truck 5 Pick-up truck 50
Other truck 6 Other truck 60
Motorcycle 7 Motorcycle 70
Other (specify) 9 Other (specify) 90
Vehicle Ownership Household member owned or leased 1 Household member owned or leased 10
(V5) Employer owned or leased 2 Employer owned or leased 20
Other (specify) 3 Other (specify) 30
Trip Purpose (A2) Home 1 Home domestic activity 10
Home paid work 11
Work and work-related 2 Main job 21
Other job 22
Volunteer work and community 23
services
Looking for work 24
Education/childcare 3 Attendance at childcare 31
Attendance at school 32
Attendance at college 33
Eating out 4 Restaurant/café 41
Fast food 42
At friends' home 43
Personal business/medical 5 Availing of/shopping for administrative 51
services
Availing of/shopping for professional 52
services
Availing of/shopping for 53
government/public services
Availing of/shopping for personal 54
services
Availing of/shopping for medical and 55
health care services
Shopping 6 Purchasing food and household 61
supplies (groceries)
Purchasing clothes, shoes, personal 62
items
Purchasing household appliances, 63
articles, equipment
Purchasing capital goods (cars, houses, 64
etc.)
Comparison shopping 65
Window shopping 66
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Sample Request for Proposals Template 73
Table 2. (Continued).
Variable Primary Category Code Secondary Category Code
Social/recreational 7 Communication/ correspondence 71
Socializing activities 72
Participating in religious/community/ 73
cultural events/activities
Visiting entertainment and cultural 74
venues
Indoor and outdoor sporting activities 75
Games/hobbies/arts/ crafts 76
Print/audio/visual media 77
Accompanying others/travel related 8 Accompanying children to places 81
Accompanying adults to places 82
Pick up or drop off other people/get 83
picked up or dropped off (private car,
car/van pool, shuttle/limousine)
Activities related to bus, public transit 84
and group rides (except car/van pool
and shuttle/limousine)
Change travel mode 85
Other (specify) 9 Not further defined (n.f.d.) 90
Means of Travel Car/van/truck driver 1 Car driver 11
(A4) Van driver 12
Truck driver 13
Car/van/truck passenger 2 Car passenger 21
Van passenger 22
Truck passenger 23
Motorcycle/moped 3 Motorcycle 31
Moped 32
Scooter 33
Bicycle 4 Bicycle 40
Walk/wheelchair 5 Walk 51
Skate/roller skate/ roller board 52
Motorized wheelchair 53
Non-motorized wheelchair 54
Bus/school bus 6 Regular bus 61
Intercity bus 62
Express bus 63
School bus 64
Train 7 Train 71
Trolley/streetcar 72
Taxi/shuttle 8 Taxi 81
Shared-ride taxi/jitney 82
Commuter van/shuttle bus: employer paid 83
Commuter van/shuttle bus: pay fare 84
Dial-a-Ride 85
Shuttle/limousine 86
Other (specify) 9 Other (specify) 90
Fuel Type Gasoline 1 Gasoline 10
Diesel 2 Diesel 20
LPG/LNG 3 LPG/LNG 30
Dual Fuel 4 Dual fuel 40
Other (specify) 9 Other (specify) 90
Employment Full-time 1 3545 hours 11
Status 4655 hours 12
Greater than 56 hours 13
Part-time 2 Less than 20 hours per week 21
Greater than 20 hours per week 22
Retired 3 Retired 31
Semi-retired 32
Full-time homemaker 4 Full-time homemaker 40
Unemployed seeking employment 5 Unemployed seeking employment 50
Unemployed not seeking employment 6 Unemployed not seeking employment 60
Full-time student 7 Full-time student 70
Child not in school/infant*to be 8 Child not in school/infant*to be 80
specified if skip mechanism not in place specified if skip mechanism not in place
Volunteer work (unpaid) 9 Volunteer work (unpaid) 90
a
Categories for Minimum and other Questions, Section 2.1.2
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74 Standardized Procedures for Personal Travel Surveys
Table 3. Required question wording.a
Question Recommended Standard for Question Wording
Household Size (H3) "Including yourself, how many people live at this address? Please do not include anyone
who usually lives somewhere else or is just visiting, such as a college student away at
school. (If further clarification is needed, include infants and children, live-in domestic
help, housemates, roomers.)"
Number of Vehicles (H6) "How many vehicles are owned, leased, or available for regular use by the people who
currently live at this address? Please be sure to include motorcycles, mopeds and RVs."
(As clarification, regular use means "are in working order.")
"How many bicycles in working condition are available to members of your household
for use in their daily travel?"
Owner or Renter Status (H7) "Do you own or rent your home?
Own/buying (e.g. paying off a mortgage);
Rent/lease; or
Provided by job or military."
Gender (P1) "Are you (is this person) male or female?"
Disability (P11) "Do you have a disability or condition that has lasted 6 or more months and that makes it
difficult to go outside the home alone, for example, to shop or visit a doctor's office?"
Activity or Trip Purpose (A2) For work or work-related activities:
Volunteer work should be specifically excluded from the definition;
The clarification should be added that work means work for pay or profit; and
Questions should be asked about a second job.
When asking for activities, include a category "Other at-home activities."
Number in Traveling Party "Including yourself, how many people were traveling with you? How many of these were
(A6) household members?"
If CATI is used, it is suggested that the follow-up question regarding number of household
members only be asked when the household size is greater than one.
At a minimum, the number in the traveling party should be asked whenever a private car,
van, or truck is the mode of travel.
Income "Please stop me when I get to the category that best describes the total combined income
for everyone living at this address for last year:"
Income response categories should match the start and end points used by the U.S. Census,
although collapsing across income categories is acceptable.
a
Standard Question Wordings, Section 2.1.3.
Table 4. Schedule of contacts and reminders.
Steps Day Contact Content Received by
Type Household
1 Advance letter Mail (R-7) Advance letter A week before recruitment
is scheduled to commence
2 Recruitment (R) Telephone Recruitment interview Recruitment day
3 R+1 Mail Survey package sent out R+3 to R+5
4 Diary Day (D)-1 Telephone Pre-Diary Day reminder (motivation D-1
call)
5 D+1 Telephone Reminder to return completed survey D+1
(motivation call)
6 D+2 Mail Postcard reminder/reset of Diary Day to D+4 to D+6
D+7
7 D+6 Telephone Reminder and check on second D+6
opportunity for Diary Day
8 D+9 Mail Postcard reminder and reset of Diary D+11 to D+13
Day to D+14
9 D+13 Telephone Reminder and check on third D+13
opportunity for Diary Day
10 D+15 Mail Re-mailing of survey package and reset D+17 to D+19
of Diary Day to D+21
11 D+20 Telephone Reminder and check on fourth D+20
opportunity for Diary Day
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Sample Request for Proposals Template 75
· The envelopes must be large, white envelopes (4 × 9.5 or larger), with the address printed
directly onto the envelope, rather than using address labels;
· The envelope shall be printed with a recognizable return address on the envelope and an
indication of the contents of the envelope (at least the survey name); and
· Postage stamps shall be affixed to the envelope, especially commemorative stamps, rather
than using a franking machine or pre-printed bulk mail.
To encourage higher response, the Contractor shall also
· Mail out a pre-notification letter that has been carefully formulated so that it is simple in
language, appealing to a wide range of people, and clearly sets forth the importance of
responding;8 and
· Provide detailed instructions in the form of an informational brochure or fact sheet.9 Care
should be taken to ensure that the information is presented in an easy to read manner, with
appropriate use of graphics where possible.
Contractor will describe in the proposal recommendations for providing survey materials in
languages other than English, and procedures for handling households that do not speak or write
in English.
Data-Collection Procedures Contractor will specify the data-collection procedures to
be used (e.g., telephone recruitment with telephone or mailback retrieval, etc.). If using tele-
phone retrieval, call-back attempts to any household must be limited to five or six attempts, and
these attempts must be made at different times on different days.10
To ensure that later calculations of response rate are standardized, the Contractor must use at
least the following four final disposition codes for households:
1. Complete interviews;
2. Eligible cases that were not interviewed (non-respondents);
3. Case of unknown eligibility; and
4. Ineligible cases.11
Table 5 presents a complete definition of households that are to be categorized in each dispo-
sition code.
The following protocol must be used for proxy reporting:12
1. For all persons, a code must be included in the database indicating whether the activity/travel
report was provided directly by the individual conducting the activities or travel or by a proxy;
2. For persons aged 14 or less, activities/travel must be reported by a parent or other adult;
3. For persons aged 1517, proxy reporting is permitted, but direct reporting with parental
permission is preferred;
4. All persons aged 18 or older must be asked directly for their activities or travel; and
5. The survey methods report must include the percent of adult respondents (persons aged 18
or older) whose activities or travel were reported by proxies (regardless of whether a completed
diary was available), excluding from the denominator persons who were physically or men-
tally unable to provide direct reporting at the time of retrieval (illness, incapacitation, etc.).
It is desired that the Contractor's calling protocol include at least one call-back attempt to obtain
a direct report from each adult household member aged 18 or older before accepting a proxy report.
8
Unit Non-Response, Section 2.2.6
9
Respondent Questions, Section 2.4.3
10
Number and Type of Contacts, Section 2.2.1
11
Computing Response Rates, Section 2.7.1
12
Proxy Reporting, Section 2.2.2
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76 Standardized Procedures for Personal Travel Surveys
Table 5. Final disposition codes for RDD telephone surveys.
Eligibility Disposition Recommended
Code
Eligible Interview 1.0
Complete 1.1
Partial 1.2
Eligible Non-Interview 2.0
Refusal and termination 2.10
Refusal 2.11
Household-level refusal 2.111
Termination 2.12
Respondent never available after call-back request 2.21
Telephone answering device (message confirms residential household) 2.22
Miscellaneous 2.35
Unknown Eligibility, 3.0
Non-Interview Unknown if housing unit 3.10
Not attempted or worked 3.11
Always busy 3.12
No answer 3.13
Telephone answering device (don't know if housing unit) 3.14
Telecommunication technological barriers, e.g., call blocking 3.15
Technical phone problems 3.16
Housing unit, unknown if eligible respondent 3.20
No screener completed 3.21
Other 3.90
Not Eligible 4.0
Out of sample 4.10
Fax/data line 4.20
Non-working number 4.31
Disconnected number 4.32
Temporarily out of service 4.33
Special technological circumstances 4.40
Number changed 4.41
Cell phone 4.42
Cell forwarding 4.43
Business, government office, other organization 4.51
Institution 4.52
Group quartersa 4.53
No eligible respondent 4.70
Quota filled 4.80
a
If specified as ineligible in the survey design.
To encourage a higher response rate, the Contractor shall provide incentives to households
unless the pretest demonstrates that a response rate in excess of 70% may be achieved without an
incentive.13 The incentives should
· Be offered only as pre-completion incentives, that is, be offered to all recruited house-
holds in the sample and not offered conditional on respondents returning a completed
survey;
· Be monetary in form and be small, on the order of $1$2 per person, except where local laws
or ordinances prohibit offering money. In such cases, a small gift should be offered; and
· Be offered to each individual and not to the household as an entity.
For a household to be deemed acceptable or "complete," the Contractor must provide the
following data from that household:
1. Responses to all of the Minimum Questions listed in Table 1.14
13
Incentives, Section 2.2.8
14
Complete Household Definition, Section 2.2.3
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Sample Request for Proposals Template 77
2. Responses from at least one person from each of the following age groups represented in
the household:
1517;
1864;
6574; and
75 and over.15
3. Sufficient information to geocode to latitude and longitude16:
No less than 99% of household addresses,
At least 95% of school and workplace addresses, and
At least 90% of other locations.
To encourage a higher response rate, the Contractor must provide a toll-free telephone num-
ber for respondents to call to verify the survey's legitimacy and to ask questions.17 The Agency will
also provide a telephone contact for respondent inquiries. For the same reasons, it is desired that
the Contractor provide an Internet website with information about the survey, links to sponsor-
ing agencies, answers to frequently asked questions, email and telephone contact for assistance or
further information, and the ability to download survey materials. It is also desirable for the Con-
tractor to provide respondents with online response capabilities.
With regard to survey procedures, the Contractor shall adhere to the following standards,
unless specifically exempted in the proposal:
· Contractor must provide a caller ID.18
· When an answering machine is reached, Contractor shall leave messages according to the
following protocol19:
When an answering machine is reached on the initial recruitment/screening call, a mes-
sage will be left at least once in the call rotation before classifying the number as non-
responding;
When an answering machine is reached on a reminder telephone call, a message will be
left; and
When an answering machine is reached during telephone retrieval of travel information,
a message will be left.
· Contractor's telephone survey protocols must include a process for complying with call
back requests, whether they occur in the recruitment or retrieval portion of a telephone
survey.20
· After the sixth request for a call back from the same household, the household may be
categorized as a "soft" refusal and therefore eligible for Contractor's "soft refusal" conversion
techniques.21
The Contractor shall exert extra effort to contact households that are difficult to contact. This
may be done by increasing the number of calls for non-contacted units, designating specific times
to call non-contacted units, expanding the data collection, and/or conducting face-to-face inter-
views.22 It is desired that the Contractor include in the proposal the costs (separately) of, and an
approach for, conducting a non-response survey.
15
Complete Household Definition, Section 2.2.3
16
Level of Geocoding to be Performed, Section 2.5.2
17
Respondent Questions, Section 2.4.3
18
Caller ID, Section 2.4.4
19
Answering Machines and Repeated Call-Back Requests, Section 2.4.5
20
Answering Machines and Repeated Call-Back Requests, Section 2.4.5
21
Answering Machines and Repeated Call-Back Requests, Section 2.4.5
22
Unit Non-Response, Section 2.2.6
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78 Standardized Procedures for Personal Travel Surveys
Task 4: Interviewer Training and Quality Assurance
In conducting the survey, the Contractor must ensure that the survey execution observes basic
practice standards regarding ethics, which include23
· The anonymity of the persons surveyed, and the confidentiality of the information they
provide, must be protected at all times.
· A survey respondent may not be sold anything or asked for money as part of the survey.
· Persons must be contacted at reasonable times to participate in the survey and must be
allowed to reschedule participation in the survey to a different time if that is more conven-
ient for them.
· Survey personnel must be prepared to divulge their own name, the identity of the Con-
tractor, the identity of the Agency, and the nature of the survey being conducted if requested
by a respondent.
· Children under the age of 15 may not be interviewed without the consent of a parent or
responsible adult.
· A respondent's decision to refuse participation in a survey, not to answer specific questions
in the survey, or to terminate an interview while in progress must be respected if that is the
respondents' firm decision.
· Respondents may not be surveyed or observed without their knowledge. Methods of data
collection such as the use of hidden tape recorders, cameras, one-way mirrors, or invisible
identifiers on mail questionnaires may only be used in a survey if the method has been fully
disclosed to the respondent and the respondent agrees to its use.
· Contractor may not release research findings prior to the public release of the findings by
Agency, unless the Agency has provided approval to do so.
· Contractor must ensure the reasonable safety of its fieldworkers during the execution of a
survey.
Contractor shall discuss its training program for interviewers, where interviewers are used, as
Agency expects that all interviewers shall receive thorough and complete training.24
Validation Survey The Contractor shall conduct a validation survey that uses (at a mini-
mum) the following three questions25:
1. Did you complete the initial survey? (yes or no). If "yes," go to Question 3 below. If "no," go
to Question 2 below.
2. Did someone else in your household complete the survey? (yes or no). If "yes," go to Ques-
tion 3 below. If "no," terminate the validation survey.
3. Question 3: Select a trip that the respondent is likely to remember from among the trips
reported in the initial survey and note the time spent at the destination. Ask the respondent
to recall the trip in question and to report the approximate time spent at the destination.
The Contractor shall report a statistic indicating the percent of validated surveys that provided
a negative answer to each of the first two questions or a mismatch on the third question.26 Agency
has established as a "tolerable" level of failure on validation the following:
· 1% level of failure on the first two questions and
· 5% level of failure on the third question.
23
Ethics, Section 2.4.1
24
Unit Non-Response, Section 2.2.6
25
Validation Statistics, Section 2.7.5
26
Validation Statistics, Section 2.7.5
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80 Standardized Procedures for Personal Travel Surveys
Table 6. Sample sizes required for specified levels of accuracy.
Measure Assumed Desired Sample Measure Assumed Desired Assumed Sample
Value Accuracy Size Value Accuracy Variance Size
Response 50% ±5% 384 Household 10 ±1 100 384
Rate 50% ±10% 96 or 10 ±2 100 96
50% ±15% 43 Person Trip 10 ±3 100 43
50% ±20% 24 Rate 10 ±4 100 24
60% or 40% ±5% 369 10 ±1 50 192
60% or 40% ±10% 92 10 ±2 50 48
60% or 40% ±15% 41 10 ±3 50 21
60% or 40% ±20% 23 10 ±4 50 12
75% or 25% ±5% 288 7 ±0.5 70 1076
75% or 25% ±10% 72 7 ±1 70 269
75% or 25% ±15% 32 7 ±1.5 70 120
75% or 25% ±20% 18 7 ±2 70 67
Non-Response 10% ±3% 384 7 ±0.5 50 768
to a 10% ±5% 138 7 ±1 50 192
Question 10% ±8% 54 7 ±1.5 50 85
10% ±10% 35 7 ±2 50 48
20% ±3% 683 4 ±0.4 40 960
20% ±5% 246 4 ±0.8 40 240
20% ±8% 96 4 ±1 40 154
20% ±10% 61 4 ±1.5 40 68
30% ±3% 896 4 ±0.4 16 384
30% ±5% 323 4 ±0.8 16 96
30% ±8% 126 4 ±1 16 61
30% ±10% 81 4 ±1.5 16 27
Task 7: Conduct Survey
Geocoding During the data collection process, the Contractor shall32
· Collect and geocode information about frequently visited locations during the recruitment
stages of the survey to maximize the opportunity to re-contact households later on to check
addresses that cannot be matched.
· Perform the geocoding for non-household and non-habitually visited locations within a
few days of data retrieval, also to allow households to be re-contacted if necessary.
· Ask respondents for the names of cross streets and/or landmarks during data retrieval.
· Use interviewers with a good knowledge of the survey area or provide interviewers with
access to gazetteers containing accurate addresses for shopping centers and schools. Online
address directories should be used to locate addresses in situations where supplementary
information is not available.
Any locations that cannot be geocoded to latitude/longitude must be referenced at least to a
traffic analysis zone (TAZ) to avoid systematic bias.33 Where it is not possible to match out-of-
region locations with a TAZ, such locations shall be assigned to a representative point outside the
study area.34 Mail-back surveys must be edited immediately upon receipt so that respondents can
be re-contacted to query missing or incorrect data times while the survey is still fresh in their
memory.35
32
Geocoding Standards, Section 2.5.1
33
Level of Geocoding to be Performed, Section 2.5.2
34
Level of Geocoding to be Performed, Section 2.5.2
35
Item Non-Response, Section 2.2.5
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Sample Request for Proposals Template 81
Task 8a: Data Coding
The data set as delivered by the Contractor shall be coded as follows36:
· All data fields must be filled with alphanumeric data (that is, blanks are not acceptable as a
legitimate code).
· Missing data--whether as the result of a respondent refusal, an indication that the respon-
dent does not know the answer, or a legitimate skip of the question--must receive a coded
numeric value. These values shall be negative values and shall be -99 for a refusal. For "don't
know" responses, it shall be -98. For legitimate skips or non-applicability of a question, the
code shall be -97.
· In any question where a legitimate response could be zero, the code for that response
must be the number zero (0). This will normally apply to any question requesting a
count of elements. In like manner, the count that is the response will be the coded value
in all cases.
· The person record must contain a count of the number of trips reported by the individual. In
this variable, a count of 0 is to be used only to indicate the response that the person did not travel
on the diary day. If no travel information was provided, then the value coded shall be -99.
· For questions to which the response is either "yes" or "no," the response of "yes" shall be
coded as 1 and the response of "no" coded as 2. For response to the gender question, "male"
shall be coded as 1 and "female" as 2.
It is required that all variables be coded using multidigit, nested codes. For example, income
shall be coded at least to the minimum coding levels and categories shown in Table 7.37
· It is desired that trip purpose/activities be coded using the either the primary, secondary, or
tertiary coding categories shown in Table 8.38 Contractor should specify the anticipated level
in the proposal; however, the final level of coding will be determined jointly by the Con-
tractor and Agency.
Table 2 in this RFP section contains desired primary and secondary coding categories for the
following complex variables39:
· Type of Dwelling (H2),
· Relationship (H4),
· Housing Tenure (H7),
· Education Level Attained (P10),
· Disability (P11),
· Race (P12),
· Vehicle Body Type (V1),
· Vehicle Ownership (V5),
· Trip Purpose (A2),
· Means of Travel (A4),
· Fuel Type, and
· Employment Status.
Should Contractor propose a different coding approach for any of the above variables, one of
the project deliverables will be a crosswalk to the desired coding categories in Tables 2, 7, and 8.
In addition, data codes must be provided in the data set as follows:
· Time of day for data entry and storage shall be coded using two fields: one for the day num-
ber and one for the time in military time (00:0023:59).40
36
Missing Values, Use of Zero, etc., Section 2.5.3
37
Coding Complex Variables, Section 2.5.4
38
Coding Complex Variables, Section 8.4
39
Coding Complex Variables, Section 2.5.4
40
Recording Time of Day, Section 2.4.7
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82 Standardized Procedures for Personal Travel Surveys
Table 7. Coding for income categories.
Minimum Detail Categories Minimum Coding More Detailed Categories More Detailed Coding
Under $10,000 00 Under $5,000 000
$5,000$9,999 005
$10,000$19,999 01 $10,000 $14,999 010
$15,000$19,999 015
$20,000$29,999 02 $20,000$24,999 020
$25,000$29,999 025
$30,000$39,999 03 $30,000$34,999 030
$35,000$39,999 035
$40,000$49,999 04 $40,000$44,999 040
$45,000$49,999 045
$50,000$59,999 05 $50,000$54,999 050
$55,000$59,999 055
$60,000$69,999 06 $60,000$64,999 060
$65,000$69,999 065
$70,000$79,999 07 $70,000$74,999 070
$75,000$79,999 075
$80,000$89,999 08 $80,000$84,999 080
$85,000$89,999 085
$90,000$99,999 09 $90,000$94,999 090
$95,000$99,999 095
$100,000$109,999 10 $100,000$104,999 100
$105,000$109,999 105
$110,000$119,999 11 $110,000$114,999 110
$115,000$119,999 115
$120,000$129,999 12 $120,000$124,999 120
$125,000$129,999 125
$130,000$139,999 13 $130,000$134,999 130
$135,000$139,999 135
$140,000$149,999 14 $140,000$144,999 140
$145,000$149,999 145
$150,000 and over 15 $150,000 and over 150
Legitimate skip 97 Legitimate skip 97
Don't know 98 Don't Know 98
Refused 99 Refused 99
· Start and end times for 24-hour diaries shall be 03:00 A.M. to 02:59A.M.41 (In the case of diaries
that cover more than 1 day, end times are extended by 24 hours for each additional day.)
· An ID number shall be assigned to each eligible address or telephone number, and this
number will remain attached to the person or household for the duration of the survey.42
· If a stratified sample is used, it is desired that the ID number be stratification-based; date-
based numbering is desirable for simple random or systemic samples.43
· Should imputation be used in the final data set to substitute for missing data items or for
values of data items that are known to be faulty, every inferred or imputed value shall be
flagged.44 Contractors should note that any imputation procedure with the exception of
overall mean imputation may be used. If hot-deck imputation is employed, it should be
conducted without replacement.
Task 8b: Interim Delivery of Data
Agency requests interim delivery of data to permit periodic review and acceptance of the com-
pleted households provided by the Contractor. This review is to be ongoing throughout the
41
Time of Day to Begin and End Reporting, Section 2.4.8
42
Creation of ID Numbers, Section 2.4.9
43
Creation of ID Numbers, Section 2.4.9
44
Missing Data Imputation, Section 2.6.3
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Table 8. Trip purpose/activity categories.
Primary Code Secondary Categories Code Tertiary Categories Code
Category
Home 01 Sleeping/napping 011 Sleeping 0110
Preparing/eating 012 Preparing a meal/snack 0121
meals/snack/drinks Eating a meal/snack 0122
Other specified food-related activities 0129
Home 013 Indoor cleaning 0131
maintenance/cleaning Outdoor cleaning 0132
Gardening/ tending plants 0134
Care of textiles and footwear 0138
Other specified home maintenance and cleaning 0139
Household management 014 Paying household bills 0141
Budgeting, organizing, planning 0142
Selling, disposing of household assets 0143
Other specified household management 0149
Personal-care activities 015 Showering, bathing, personal grooming 0151
Health/medical care to oneself 0152
Receiving personal care from others 0153
Other specified personal-care activities 0159
Using computer/telephone 016 Using telephone (fixed line) (not including telephone 0161
shopping)
Using cell phone (not including telephone shopping) 0162
Sending/reading/receiving email 0163
Internet browsing (not including online shopping) 0164
Shopping for goods and services using telephone 0165
(fixed line)
Shopping for goods and services using cell phone 0166
Shopping for goods and services using Internet 0167
Other specified use of computer/telephone 0169
Caring for others 017 Caring for children 0171
Teaching, training, helping children 0172
Caring for adults 0173
Other specified caring for others 0179
Paid work 018 Paid work main job 0181
Paid work other job 0182
Other specified at home paid work 0189
Other specified at home 019 n.f.d. 0190
activities
Work 02 Main job 021 Regular hours 0211
Overtime hours 0212
Extra hours (not paid as overtime) 0213
Other specified main job activities 0219
Other job 022 Regular hours 0221
Overtime hours 0222
Extra hours (not paid as overtime) 0223
Other specified job activities 0229
Work in internship, 023 Regular hours 0231
apprenticeship, etc. Overtime hours 0232
Extra hours (not paid as overtime) 0233
Other specified internship/apprenticeship activities 0239
Unpaid work in family 024 n.f.d. 0240
business
Breaks and interruptions 025 n.f.d. 0250
from work
Training and studies in 026 n.f.d. 0260
relation to work
Volunteer work and 027 n.f.d. 0270
community services
Looking for work/setting 028 Looking for work 0281
up business Looking for/setting up business 0282
Other specified work 029 n.f.d. 0290
related activities
Education/ 03 Attendance at childcare 031 n.f.d. 0310
Childcare Attendance at school 032 n.f.d. 0320
Activities Attendance at college 033 n.f.d. 0330
Breaks/waiting at place of 034 n.f.d. 0340
general education
Self study for distance 035 n.f.d. 0350
education course work
(continued on next page)
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Table 8. (Continued).
Primary Code Secondary Categories Code Tertiary Categories Code
Category
Homework, study, 036 n.f.d. 0360
research
Career/professional 037 n.f.d. 0370
development training and
studies
Other specified activities 039 n.f.d. 0390
relating to
education/childcare
Eating Out 04 Restaurant/café 041 Restaurant 0411
Café/snack bar/cafeteria 0412
Fast food 042 Take out 0421
Eat in 0422
At friends' home 043 n.f.d. 0430
Picnicking 044 n.f.d. 0440
Other specified eating out 049 n.f.d. 0490
Personal 05 Availing of/shopping for 051 Post Office 0511
Business administrative services Other specified administrative service 0519
Availing of/shopping for 052 n.f.d. 0520
educational services
Availing of/shopping for 053 Banking/credit union 0531
professional services Insurance 0532
Real estate 0533
Tax or accountant 0534
Legal services 0535
Other specified professional services 0539
Availing of/shopping for 054 n.f.d. 0540
government/public
services
Availing of/shopping for 055 Hairdresser/barber/beautician 0551
personal services Other specified personal service 0559
Availing of/shopping for 056 Medical 0561
medical and healthcare Dental 0562
services Eye care 0563
Physiotherapy 0564
Other specified healthcare service 0569
Availing of/shopping for 057 n.f.d. 0570
rental services
Availing of/shopping for 058 n.f.d. 0580
repair and maintenance
services
Other specified activities 059 n.f.d. 0590
relating to personal
business
Shopping 06 Purchasing food and 061 n.f.d. 0610
household supplies
(groceries)
Purchasing clothes, shoes, 062 n.f.d. 0620
personal items
Purchasing school 063 n.f.d. 0630
supplies
Purchasing medical 064 n.f.d. 0640
supplies
Purchasing household 065 n.f.d. 0650
appliances, articles,
equipment
Purchasing capital goods 066 n.f.d. 0660
(cars, houses, etc.)
Comparison shopping 067 n.f.d. 0670
Window shopping 068 n.f.d. 0680
Purchasing other specified 069 n.f.d. 0690
goods.
Social and 07 Communication/ 071 n.f.d. 0710
Recreational correspondence
Activities Socializing activities 072 Doing activities/going to places and events together 0721
Receiving visitors 0722
Visiting friends and relatives 0723
Other specified socializing activities 0729
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Table 8. (Continued).
Primary Code Secondary Categories Code Tertiary Categories Code
Category
Participating in 073 Participating in community celebration of 0731
religious/community/ historical/cultural events
cultural events/activities Participation in non-religious community rites of 0732
weddings, funerals, births, etc.
Participating in community social functions 0733
Participating in religious activities 0734
Participating in other specified 0739
religious/community/cultural activities
Visiting entertainment and 074 Attendance at movies/cinema 0741
cultural venues Attendance at concerts 0742
Attendance at sporting events 0743
Attendance at library 0744
Attendance at amusement park 0745
Attendance at museum/exhibition/art gallery 0746
Attendance at zoo/animal park 0747
Attendance at other specified entertainment and 0749
cultural venues
Indoor and outdoor 075 Organized sport 0751
sporting activities Informal sport 0752
Exercise (excludes walking) 0753
Walking, hiking, bushwalking 0754
Fishing, hunting 0755
Driving for pleasure 0756
Participation in other specified indoor and outdoor 0759
sporting activities
Games/hobbies/arts/ crafts 076 Card, paper, board games, crosswords 0761
Gambling 0762
Arcade games 0763
Home computer games 0764
Hobbies, handwork, crafts 0765
Other specified activities relating to 0769
games/hobbies/arts/crafts
Print/audio/visual media 077 Reading 0771
Watching/listening to television/video programs/radio 0774
Other specified activities using print, audio or visual 0779
media
Other specified social and 079 n.f.d. 0790
recreational activities
Accompan- 08 Accompanying children to 081 Accompanying children to receive personal services 0811
ying/helping places Accompanying children to receive medical/health 0812
others and services
travel- Accompanying children to school, daycare centers 0813
related Accompanying children to sports lessons, etc. 0814
Accompanying children to other specified places 0819
Accompanying adults to 082 Accompanying adults to receive personal services 0821
places Accompanying adults to receive medical/health services 0822
Accompanying adults for shopping 0823
Accompanying adults for social activities 0824
Accompanying adults to cultural, sports, and 0825
entertainment venues
Accompanying adults to other specified places 0829
Pick up or drop off other 083 Pick up someone or get picked up 0831
people/get picked up or Drop off someone or get dropped off 0832
dropped off (private car,
car/van pool,
shuttle/limousine)
Activities related to bus, 084 Wait for/get on vehicle 0841
public transit, and group Leave/get off vehicle 0842
rides (except car/van pool
and shuttle/limousine)
Change travel mode 085 n.f.d. 0850
Other specified activity 089 n.f.d. 0890
related to accompanying
others or travel-related
No activity 09 No activity 091 n.f.d. 0910
No recorded activity 092 n.f.d. 0920
No further activity recorded 093 n.f.d. 0930
Other 99 n.f.d. 990 n.f.d. 9900
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86 Standardized Procedures for Personal Travel Surveys
data-collection period. Ongoing review provides both Agency and the Contractor the opportu-
nity to make mid-course corrections and manage expectations.
Task 9: Delivery of Final Data Set
Interim and final datasets shall be delivered in ASCII format, as portable SAS or SPSS files.45
If the travel data base contains two or more related files, the variables that link the files together
must be in each file. The Contractor must provide the following data files at the conclusion of
the survey for archival purposes:
1. The raw data files,46
2. The call-history files describing call dispositions during the recruitment process (if tele-
phone recruitment was used),47 and
3. Partial data from incomplete households.48
Task 10: Analysis of Results
The Contractor shall report response rates using the formula developed by the American Asso-
ciation of Public Opinion Research (AAPOR), RR3A, as shown in Equation 1.49 The estimation
of eligibility rate will be determined jointly by the Contractor and Agency.
SR
RR3 A = (1)
( SR + PI ) + ( RB + O ) + e A (UH + UO + NC )
where
SR = number of complete interviews/questionnaires,
PI = number of partial interviews/questionnaires,
RB = number of refusals and terminations,
O = other,
NC = number of non-contacts,
UH = unknown if household occupied,
UO = unknown other, and
eA = estimated proportion of cases of unknown eligibility that are eligible (AAPOR eligibil-
ity rate: the same formula for calculating the eligibility rate is used).
The Contractor will conduct a weighting and expansion exercise and shall include the
weights in the data set along with a description of the weighting process in the metadata.50
The weights must include expansion factors so that the sum of the weights matches popula-
tion estimates. The weighting and expansion process must follow the two-stage procedure
described below.
Stage 1 To establish household weights, Stage 1 of the weighting and expansion process
should include the following steps:
1. Estimate an initial weight equal to the inverse of the design sampling rate. If dispropor-
tional sampling is used, weights should be estimated for each stratum separately. The ini-
tial weight of household i in stratum h is
45
Data Archiving, Section 2.6.4
46
Data Archiving, Section 2.6.4
47
Data Archiving, Section 2.6.4
48
Complete Household Definition, Section 2.2.3
49
Computing Response Rates, Section 2.7.1
50
Weighting and Expansion of Data, Section 9.2
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Sample Request for Proposals Template 87
1
w i ,exp =
sh ,ih
where
wi,exp = initial weight (or expansion factor) for household i, and
sh,ih = design sampling rate in stratum h of which i is an element.
2. If knowledge is available on levels of non-response in the survey at geographic or demo-
graphic subdivision level, establish a weight to account for differential non-response. If non-
response is not known at a level that subdivides the sample, assume the weight for this step
is 1 and proceed to the next step. If the response rate is known at a level that subdivides the
sample, the response weight for household i in subdivision j is
1
w i ,resp =
rj ,ij
where
wi,resp = response weight for household i, and
rj,ij = response rate in subdivision j of which i is an element.
3. Weight for difference in selection probabilities. This is necessary when the sample frame and
the sampling unit do not coincide as, for example, when the sample frame is residential tele-
phone numbers and the sampling unit is households. Households with more telephone lines
are more likely to be selected under this system than households with fewer lines. The same
applies if the sample frame is dwelling units and multiple households occupy some dwelling
units. To account for these differential selection probabilities, the following weight should
be applied to the households, where a one-to-one relationship between the sample frame
and the households does not exist:
1
w i ,sel =
ui
where
wi,sel = selection weight for observation i, and
ui = number of times household i is represented in the sample frame.51
4. Obtain a composite weight for each household by multiplying the weights from the equa-
tions in Steps 1, 2, and 3 together:
w i = w i ,exp × w i ,resp × w i ,sel
The weights identified for households in Stage 1 are also assigned to the persons and trips in
the household.
Stage 2 Separate weighting is conducted for households and persons. While the procedure
used is similar, different variables are used in each weighting process. Final weights for households
are identified by conducting the following steps:
1. Identify household variables for which population values are available (from external
sources) and which also occur within the sample. The choice of variables should be dictated
51
Note that ui can range from a fraction for those households who share a dwelling or telephone line (or are
episodic telephone owners) to values in excess of 1 when a household owns multiple telephone lines or inhabits
more than one dwelling in the study area.
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88 Standardized Procedures for Personal Travel Surveys
by the purpose of the survey, where bias is most expected, and the reliability of popula-
tion values.
2. Break each variable into a manageable number of categories. The categories must be selected
so as to ensure that the multidimensional "cells" that are produced by simultaneously cross-
classifying all variables, all contain at least some sample values, because empty cells cannot
be adjusted by weights and are, therefore, redundant. Individual cells can be collapsed into
single larger cells to eliminate empty cells.
3. Sum household weights, established in Stage 1, in each cell.
4. Apply iterative proportional fitting to the cell weights identified above. The order in which the
variables are considered in each iterative cycle is irrelevant since a unique solution is guar-
anteed irrespective of the order of the variables. A closing error of no more than 1% on any
marginal value is recommended.
5. Identify final weights by dividing the final cell weights above by the sum of the households in each
cell. This is effectively dividing the weighted sum of households in each cell by the unweighted
sum to produce a common weight for all households that belong in each cell. Note that while
individual households had different weights at the end of Stage 1, households in the same cell
now have the same weight. However, the effect of those individual weights did have an impact
in structuring the seed n-dimensional matrix used in the iterative proportional fitting process
employed here. The adjustments in Stage 2 represent a further improvement in Stage 1
weights, but, because cell totals are used in the process, individual weights are lost.
6. Transfer the final household weights to the data and include a description of the expansion and
weighting process in the metadata.
7. Establish person weights in the same manner as was accomplished with household weights with
the exception that person variables are used in the process and person weights from Stage
1 are used in the initial (seed) n-dimensional matrix. Final person weights are established
by dividing the final cell values by the number of persons in each cell.
8. Establish trip weights by applying person weights to each trip. The sum of all trip weights in
the sample will then represent the total number of trips made in the study area during the
survey period although trip under-reporting will tend to result in this estimate being lower
than the true number of trips conducted. Separate trip weights cannot be established
because the true number of trips made in an area is unknown.
Task 11: Final Report
In addition to other data tables and information required by Agency, the final documentation
must include the following information:52
· Identification--clear identification of the sponsoring Agency(ies), the Contractor, and the
name(s) of the Contractor's subcontractors and/or fieldwork agency(ies), if any.
· Survey purpose and objectives--description of why the survey is being conducted, what it
hopes to achieve, and the expected results.
· Copies of the questionnaire and other survey documents--this includes the wording of all ques-
tions including specific interviewer and respondent instructions and aids such as recruitment
scripts, interview script (telephone and personal interview), maps, travel diaries, memory
joggers, etc. These should be provided in an appendix.
· Other useful survey materials--interviewer instruction manuals, validation of results (tech-
niques employed), codebooks, and incentive descriptions (monetary levels offered).
· Population and sampling frame--a description of the population that the survey is intended
to represent as well as why this population was selected and a description of the sampling
frame used to identify this population.
52
Documentation, Section 2.6.5
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Sample Request for Proposals Template 89
· Sample design--a complete description of the sample design: sample size, sampling frame,
information on eligibility criteria, and screening procedures.
· Sample selection procedures--methods by which respondents were selected by the Contrac-
tor, details of how the sample was drawn, the levels of proxy reporting, what constituted a
complete household, and the sample size.
· Sample disposition--refusals, terminations, ineligibles, completed interviews, and non-
contacts. Also a description of the level of item non-response accepted for key variables
and why.
· Response rates--how the eligibility rate for the unknown sample units was determined, a
description of the AAPOR response rate formula used, as well as the calculation of the over-
all response rate.
· Processing description--editing, data adjustment, and imputation procedures used.
· Precision of estimates--sampling error and include other possible sources of error to inform
user of accuracy or precision and a description of weighting or estimating procedures.
· Basic statistics--a description of all base percentages or estimates on which conclusions are
made.
· Data collection methods--survey mode and procedures.
· Survey period--dates of interviews of fieldwork or data collection and reference dates for
reporting--that is, time, day, and date when calls or other forms of contact were made.
· Interviewer characteristics--number and background of fieldwork staff.
· Quality indicators--results of internal validity checks and any other relevant information
such as external research.
· Contextual information--any other information required to make a reasonable assessment
of the findings and data.
· Geocoding description--including how geocoding was conducted, the level of data imputa-
tion and inference, and how these values are flagged, etc.
The Contractor will assist the Agency in collecting the necessary organizational documenta-
tion: the RFPs, proposal submission, contract and modifications, progress reports, key meeting
results, key personnel costs, and information about situations that occurred during the survey
period.
The final report shall include the following as quality indicators:
· An overall estimate of item non-response that shall be calculated as the average item-non-
response and expressed as a percentage to the following key questions53:
Means of travel,
Licensed driver status,
Start time and end time of trip or travel time of trip, and
Vehicle occupancy.
· Note that item non-response includes those items where values are missing, where the
respondent has indicated that they "don't know" and where the respondent has refused to
answer.
· The percent of non-mobile days.54 If questions are asked regarding the reasons why no travel
occurred, as an advanced standard, the report must include analyses of these reasons and the
characteristics of persons who reported no travel.
· An estimate of coverage error, calculated as the percentage deviation of the population of the
study area estimated using the planned sample from that of the population of the same area
53
Item Non-Response, Section 5.5
54
Incorrect Reporting of Non-Mobility, Section 7.6
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90 Standardized Procedures for Personal Travel Surveys
using a reliable external source. Coverage error must be estimated using the definition of
coverage error in Equation 2 below55:
F
CE = 1 - x 100 (2)
X%
where
CE = coverage error in percent,
Fx = sample population multiplied by the inverse of the sampling rate, and
~
X = population from an external source.
· An assessment of sample bias, using the following procedure.56
· The following variables should be used to test for bias:
household size;
vehicle availability;
household income (if collected);
race of each person in the household;
age of each person in the household; and
gender of each person in the household.
· The variables should be measured as follows:
household size: mean value;
vehicle availability: categories of 0, 1, 2, and 3+;
household income: categories corresponding to those in Table 7;
race: categories of white, black/African American, American Indian/Alaska native, Asian,
Native Hawaiian/Pacific Islander, other single race, and two or more races;
age: categories of 05, 610, 1114, 1517, 1864, 6574, 75 and over;
gender: male and female.
· Total error should be measured using the percentage RMSE statistic defined in Equation 3:
2
rij - sij
ni n ji
1 1
Percent RMSE = n rij
× 100 (3)
ni i ji j
where
ni = number of variables i;
nji = number of categories j in variable i;
rij = reference value of variable i in Category j;
sij = sample value of variable i in Category j.
· A data cleaning statistic (DCS), calculated using the following procedure57:
N I
count ( xi ,n )
DCS = n i
N ×I
where
xi,n = ith data item of respondent n,
{
count ( x i ,n ) =
1 if i th data item of respondent n was cleaned
0 otherwise }
55
Coverage Error, Section 10.3
56
Assessing Sample Bias, Section 9.1
57
Data Cleaning Statistics, Section 2.7.6
