National Academies Press: OpenBook

On-Board and Intercept Transit Survey Techniques (2005)

Chapter: Chapter Five - Survey Fieldwork and Data Processing

« Previous: Chapter Four - Developing Questionnaires
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Suggested Citation:"Chapter Five - Survey Fieldwork and Data Processing." National Academies of Sciences, Engineering, and Medicine. 2005. On-Board and Intercept Transit Survey Techniques. Washington, DC: The National Academies Press. doi: 10.17226/13866.
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Page 40
Page 41
Suggested Citation:"Chapter Five - Survey Fieldwork and Data Processing." National Academies of Sciences, Engineering, and Medicine. 2005. On-Board and Intercept Transit Survey Techniques. Washington, DC: The National Academies Press. doi: 10.17226/13866.
×
Page 41
Page 42
Suggested Citation:"Chapter Five - Survey Fieldwork and Data Processing." National Academies of Sciences, Engineering, and Medicine. 2005. On-Board and Intercept Transit Survey Techniques. Washington, DC: The National Academies Press. doi: 10.17226/13866.
×
Page 42
Page 43
Suggested Citation:"Chapter Five - Survey Fieldwork and Data Processing." National Academies of Sciences, Engineering, and Medicine. 2005. On-Board and Intercept Transit Survey Techniques. Washington, DC: The National Academies Press. doi: 10.17226/13866.
×
Page 43

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Data collection is one of the most important phases of on-board and intercept surveys—and also one of the most challenging. Fieldwork is challenging because the locus and scope of the project expands. Although survey planning involves a rela- tively small number of people in centralized offices, fieldwork involves a relatively large number of survey workers, supervi- sors, and respondents, usually spread over a geographically dis- parate area. Project staff generally has less direct control and oversight of this phase of the overall survey project than any other project phase. Planning for data collection takes into account four primary considerations: costs, data quality, duration, and manageability. Each of these considerations is affected by the method of data collection. Who will be used as survey workers? How will they be recruited, trained, and super- vised? How will workers be deployed in the field? How will their safety be ensured? How will the quality of their work be monitored? To some extent choices may necessitate tradeoffs. Deploying survey workers in pairs may increase response rates, data quality, and safety but also increase costs. Obtain- ing survey workers from a temporary employment agency may reduce staff time for fieldwork but increase the amount of training and supervision needed. On the other hand, some choices may be beneficial across the board. For example, using a pool of experienced part-time survey workers may reduce costs for training and supervision while also improv- ing data quality. Planning for survey data collection can leverage the core strength of on-board and intercept surveys; namely, the direct contact between survey workers and transit riders. Friendly, courteous, and engaging survey workers can achieve response rates equal to or greater than response rates for other types of surveys. Survey workers can answer ques- tions and assist respondents as necessary. Survey workers can also disburse small-value incentives, such as free ride coupons, directly to respondents. The survey team can accu- rately track the total number of surveys completed as they are received. Tracking is particularly useful in surveys with route, location, and/or time-of-day quotas, because survey workers can be kept in the field until the target number of surveys is obtained for each stratum. Data processing can begin as completed surveys start to arrive, thus speeding the pace of the project. 40 Data collection planning must also address the some- times-daunting challenges that are inherent to fieldwork. Survey staff must be recruited and trained. Supervision and monitoring must be arranged for geographically dispersed survey workers. Unpredictable events ranging from adverse weather to accidents or other disruptions in transit service must be dealt with, often with little or no warning. While adhering to the sampling plan, survey workers need to be deployed with an eye toward cost-efficiency. Key steps in data collection are: • Identification and recruitment of survey staff, • Survey staff training, • Supervision, and • Safety. IDENTIFICATION AND RECRUITMENT OF SURVEY STAFF Data collection can be carried out by in-house transit agency staff, consultants, or academic institutions. Most transit agencies surveyed have used both consultants and in-house staff for on-board and intercept fieldwork in the previous 3 years. Approximately 7 in 10 agencies reported using tran- sit agency staff, and about the same proportion have used consultants for one or more surveys in the past 3 years. By contrast, only 8% used academic institutions for any fieldwork during this period. Looking specifically at the 58 on-board and intercept sur- veys that transit agencies reported on in detail, fieldwork was conducted as follows: • By consultants (50%), primarily using a combination of permanent staff (e.g., supervisors) and temporary work- ers hired for the purpose. • By transit agency staff (34%), primarily by permanent staff or, in a few cases, by part-time workers hired directly by the agency. A few agencies use a combina- tion of permanent and temporary staff. • By a combination of transit agency and consultant staff (12%). • By academic institutions (3%). Transit agencies are inclined to use in-house staff for relatively small surveys involving samples of 2,000 or fewer CHAPTER FIVE SURVEY FIELDWORK AND DATA PROCESSING

41 riders. Agency staff can be diverted from staff functions for a period of a few days at most to carry out the survey. When used, temporary staff hired directly by transit agencies often work part-time for extended periods on one or more surveys. Some agencies reported innovative approaches to obtain- ing survey staff at minimal cost. CTA recruits survey workers through postings on college campuses. These “volunteers” are compensated with free fare media and work no more than a few days a month. The episodic nature of the work matches both the students’ availability and CTA’s needs. One volun- teer has worked for several years and become quite skilled at obtaining a high response rate. The quality of available temporary workers can affect the duration of data collection. For example, the Greater Portland (Maine) Council of Governments chose to use a smaller number of reliable staff over a 3-week period rather than have a large concentration of temporary staff finish the survey in 1 week. Conversely, the Oshkosh Transit System found that a condensed 2-day time frame to collect data using temporary in-house staff worked extremely well. Larger surveys tend to exceed the in-house resources of transit agencies. Therefore, consultants are typically used for surveys requiring samples of 5,000 or 10,000 or more riders. Consultants usually bring in temporary workers obtained from temporary agencies or the consultant’s own recruitment efforts. Here too, duration of surveying can affect costs and data quality. It is likely to be less expensive for a consultant to field a survey on a continuous basis than to conduct the survey in a “blitz” implementation. Continuous surveys need fewer sur- vey workers at any one time and will, by their nature, use more experienced survey workers. Costs for training and supervi- sion will also be lower. MARTA’s Systemwide Survey is a good example of the benefits of continuous surveying. SURVEY STAFF TRAINING Although data collection tasks such as distributing and collecting surveys may seem to require minimal skills, the experience of transit agencies is that some potential survey workers are much more effective than others. The aptitudes required are actually quite varied. Survey workers must be punctual and able to identify and reach the correct survey location. They must give attention to detail in tracking sur- veys, yet also be reasonably outgoing in greeting passengers. Survey workers must be able to greet passengers with a friendly countenance and a direct gaze. They must possess the stamina to work on a moving bus or train for hours at a time. They must also have the fortitude and good judgment to mollify the occasional disgruntled rider or bus operator. Given the breadth of aptitudes required, proper training of survey staff is essential. Training is designed to ensure that survey procedures are carried out properly and to maximize response rates. Training may cover a range of topics: • Survey purposes, • Deployment and scheduling, • How to approach passengers, • How to aid passengers who request assistance in com- pleting the survey, • Tracking refusals, • Safety, • Dress, • Behavior and courtesy, and • Record keeping. Survey workers are often provided with detailed written instructions. The instructions list tasks to be completed at the start of the shift, during survey administration, and at the end of the shift. Training typically takes between 30 min and 4 h, although a large survey for Pinellas Suncoast Transit Authority involv- ing on-board interviewing required a full day of training. The length of training depends primarily on the experience level of the survey workers. New temporary workers are often given 4 h of training, whereas experienced survey staff may only need 30 to 60 min to become familiar with the current operation. For new survey workers in particular, training is likely to include role playing of the interaction with customers. Role playing helps survey workers learn how to approach riders in a friendly, courteous manner to maximize participation in the survey. Role playing may also cover action regarding refusals and problem situations. Effective training is critical to the overall success of on- board and intercept surveys. Transit agency staff surveyed for this report cited friendly and experienced survey staff, outgoing personalities, and proper appearance as key factors affecting data quality and response rates. SUPERVISION In addition to recruiting and training survey workers, effec- tive supervision and monitoring is critical to the success of the data collection effort. Proper supervision is crucial to ensuring that survey staff is at their assigned locations and carrying out survey procedures. Transit agencies reported experiences in which surveyors went absent without notice and in which they falsified data. Supervisors generally issue work assignments to survey staff at the beginning of each shift. For assignments that begin in the early morning, assignments are usually made on the previous day. In either case, survey workers turn in surveys collected from the previous shift and are given their next assignment. Supervisors can check the surveys at this time for quality and completeness.

The work of survey staff is often reviewed during the fieldwork as well as at the end of the shift. Supervisors may randomly observe and monitor surveyors on board buses and trains or at transit centers. Some agencies also use “mystery shoppers” (anonymous observers) to monitor sur- veyors. One agency asks drivers to report any problems with survey administration. Transit agencies (and their consultants) employ a vari- ety of approaches to dispatching survey workers to their starting locations. The approach depends on the configura- tion of the transit service, time of day, and other factors. In large bus surveys using temporary workers, for exam- ple, survey workers are often required to provide their own transportation to the starting location. Staff may be board- ing the first bus run of the morning at bus garages in relatively remote parts of town and public transportation may not be available. In other situations, most or all bus routes serve a central terminal such as a downtown transfer center. Dispatching survey workers from a terminal facilitates close supervision from a central location. An important consideration for on-board bus surveys involves bus operators. Transit agencies noted that bus oper- ators must be aware that a survey will be conducted and must feel comfortable with having survey workers on the bus. The workers must not interfere with passenger boarding. Los Angeles County Metropolitan Transportation Authority (Metro) has surveyors board buses at the terminal rather than on the street. This ensures that the surveyor boards the correct bus and that the bus operator trusts the surveyor. The surveyor rides out to the bus in a support vehicle with the operator if it is a second or third shift. SAFETY One-third of transit agencies surveyed reported taking steps to protect survey workers’ physical safety, whether from crime or accidents. Agencies issue high-visibility or fluores- cent safety vests to protect against accidents, and also to convey to the public that these workers are part of the transit system. During training, survey workers may be instructed on when to stand on buses or trains and when to be seated to avoid injury. Surveyors working on trains are sometimes given rail safety instruction. To address concerns about crime, transit agencies have sur- veyors work in teams of two, particularly at night. Agencies sometimes limit the hours the survey is conducted (to the 8 a.m. to 5 p.m. period, in one case) and avoid assigning female surveyors to night shifts. Agencies also issued workers identification badges, alerted police officials to survey sched- ule dates, and notified bus operators that survey workers would be on their buses. 42 DATA CLEANING AND DATA PROCESSING Once surveys have been returned from the field, the task of checking, cleaning, and tabulating the data can be substan- tial. This is especially the case for large O&D surveys where addresses, intersections, and landmarks must be geocoded. Particularly in the case of O&D surveys, transit staff emphasizes the importance of beginning data editing and coding as soon as surveys are completed. That way, correc- tive action can be taken to mitigate aspects of the fieldwork that may be affecting data quality. In addition, the overall workflow goes more smoothly if data collection commences during the fieldwork. Transit agencies report various requirements and proce- dures for completeness, data editing, and cleaning. Agencies also use a variety of software for data processing and analysis. Completeness More than one-half of agencies surveyed required that either a certain percentage of questions be answered or that certain key questions be answered for the survey to be considered complete and usable. The percentages used ranged from 25% to 90%; most agencies that used this approach cited a percentage of more than 50%. Agencies that required certain key questions to be answered tended to focus on questions related to O&D, trip purpose, and fare type. Greater Portland (Maine) Transit District required that the O&D questions be completed. WMATA required that O&D and jurisdiction of residence be completed. TriMet’s Annual Fare Survey required that fare and transfer questions be answered. Sun Tran required that O&D and other trip-specific questions be answered, but not satisfaction and demographic questions. Four in 10 agencies surveyed required that all questions on the survey be answered for the survey to be considered complete and usable. Many of these were short surveys or surveys conducted by means of personal interviews. However, self-administered surveys for the Lane Transit District, Fort Worth Transportation Authority, Milwaukee County Transit System, Metra (Chicago area), Southwest Ohio Regional Transit Authority, Potomac & Rappahan- nock Transportation Commission, Transit Authority of Northern Kentucky, Tompkins Consolidated Area Transit, Southeastern Pennsylvania Transportation Authority (SEPTA), Sacramento Regional Transit District, and Merrimack Valley Regional Transit Authority required that all questions be answered. Six in 10 O&D surveys reported by transit agencies required that all O&D survey questions be answered for the survey to be considered complete and usable. Agencies not requiring that all O&D information be complete generally

43 required that at least one part of the start of the trip (origin or boarding) and one part of the end of the trip (alighting or des- tination) be complete. Data Editing and Cleaning Two in three transit agencies surveyed implemented editing procedures or other steps in data cleaning and data processing to ensure the accuracy of the data. Most commonly, agencies checked for logic and consistency in the answers—e.g., whether transfers made sense based on the routes involved and eliminating self-reported “home to home” trips. Other procedures were to eliminate outliers in the data based on the number of standard deviations from the mean and proofing the accuracy of data input. For O&D surveys many agencies conducted extensive address editing procedures to geocode as many locations as possible. Data processing procedures included checking the consistency of trip direction, distance, and speed with O&D locations and transit routing information; verifying addresses against geographic information system databases, and using landmark look-up tables. See Table 17 for survey results on data processing for address information. Consultants (or academic institutions) were responsible for data cleaning and data processing for 64% of the surveys reported by transit agencies. The transit agency was respon- sible for these tasks in 23% of the surveys. The consultant and agency shared data cleaning and data processing duties in the remaining 13% of surveys. Tabulating Several database software packages are used for tabulating survey results. Surveys reported by transit agencies used both traditional database software such as SPSS, Microsoft Access, and SAS, and spreadsheet software such as Microsoft Excel (Table 18). Some agencies have had positive experiences with using scanners to input data. Scanning reduces data entry needs and can produce data quickly. Other agencies how- ever have found that the intelligence applied during data entry (especially O&D data) is essential to the process and cannot be replicated using scanners. Some agencies have also found that scanners introduce errors during the data capture process and as a result, take more time than man- ual data entry. Action taken Percentage O&D direction logical with bus/train direction Looked at route/line used for trip Used logic or consistency checks Verified addresses/intersections using GIS software Used landmark listing Speed of trip logical for O&D distance and time of trip provided by respondent Speed and distance reasonable for origin–boarding and alighting–destination pairs based on mode of access/egress (e.g., don’t walk 20 miles or at 60 mph) Other 62 62 57 48 43 10 5 38 Total number of respondents, 21. O&D = origin and destination; GIS = geographic information system. TABLE 17 STEPS TAKEN IN VALIDATING ADDRESS DATA TABLE 18 SOFTWARE USED IN TABULATING RESPONSES Software SPSS Microsoft Excel Microsoft Access SAS Wincross Other software, primarily GIS software Percentage 50 12 14 50 9 3 Total number of respondents, 19. GIS = geographic information system.

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TRB’s Transit Cooperative Research Program (TCRP) Synthesis 63: On-Board and Intercept Transit Survey Techniques examines transit agencies’ experiences with planning and implementing on-board and intercept surveys. On-board and intercept surveys include self-administered surveys distributed on board buses and railcars, and in stations, as well as interviews conducted in these environments. The report provides an overview of industry practices and covers a broad range of issues addressed in planning a given survey.

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