Technical Appendix to NCHRP Report 571: Standardized Procedures for Personal Travel Surveys (2007) / Chapter Skim
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Pages 71-124
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65 CHAPTER 5 5. Design of Data Collection Procedures 5.1 D-1: NUMBER AND TYPE OF CONTACTS 5.1.1 Definition This item is about how many times and by what methods households should be contacted to obtain complete household responses.
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66 letter, as well as distinctive postage markings13, also play a role (Zmud, 2003)
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67 quite annoyed: the disruption to their cultural activity(ies) being perceived as a lack of respect.
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68 to Stec et al., (1999) and Colombo (2000)
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69 Table 32: Statistical Tests between Number of Call Attempts and Type of Contact, File 1 Contact type Chi –Square Df Cramer's V Cold call * 4917.93 19 0.406 Pre-notified *
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70 It is interesting to observe that of the 612 complete recruitment interviews achieved after a second call was made to the household, 75.7 percent, or 209 of these, were converted to complete household surveys. The percentages of conversions from call backs to complete recruitment interviews, and from call backs to complete recruitment interviews to complete household surveys, are almost identical for each call.
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71 Complete Recruitment Converted (%) n/a 52.1 23.6 14.7 8.4 1.2 0 0 0 0 100% Noncontacts to Complete Interview n/a 638 291 168 92 17 0 0 0 0 1,206 Converted (%)
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72 Using this procedure, it would not be expected that much difference would occur in the initial screener interviews, since rapport was not yet established at that time. Also, because Westat used a manual dialing procedure for the pilot survey, compared to the automated call assignment system of the CATI software for the balance of the sample, it is possible that the initial screener interviews would be less successful than those not in the pilot survey.
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73 5 D+1 Telephone Reminder to return completed survey (motivation call) D+1 6 D+2 Mail Postcard reminder/reset of Diary Day to D+7 D+4 to D+6 7 D+6 Telephone Reminder and check on second opportunity for Diary Day D+6 8 D+9 Mail Postcard reminder and reset of Diary Day to D+14 D+11 to D+13 9 D+13 Telephone Reminder and check on third opportunity for Diary Day D+13 10 D+15 Mail Re-mailing of Survey Package and reset of Diary Day to D+21 D+17 to D+19 11 D+20 Telephone Reminder and check on fourth opportunity for Diary Day D+20 5.2 D-3: PROXY REPORTING 5.2.1 Definition In surveys that use telephone or personal interviews as the method to retrieve completed data, there is a continual issue regarding who provides the activity or travel information: the person performing the activity or travel (direct respondent)
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74 Acceptable Proxy Reports There are clear instances in which having someone else report activities is not only appropriate, but desirable. Foremost among these instances is the reporting of children's activities or travel.
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75 directly. There is a standard question recommended regarding long-term disabilities that would prevent an individual from traveling alone outside the home (section 4.3)
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76 1. Lower response rates; and 2.
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77 Table 39: Summary Features of Nine Data Sets Examined Characteristic New York Metropolitan Transportation Council Household Interview Survey Bay Area Main Travel Survey 2000, Dallas-FortWorth Travel Survey South East Florida Household Travel Survey Broward Household Travel Survey Oklahoma Kentucky Indiana Activity and Travel Survey Little Rock Household Travel Survey Yakima, Charleston and Wilmington National Household Travel Survey Complete Response Definition All records for all household members All household members to provide travel and activity information All records for all household members All household members to provide travel information All household members to provide travel information All household members to provide travel and activity information All household members to provide travel and activity information All household members to provide travel and activity information 50% of adults in household complete the person interview. Proxy Reporting Accepted if an adult reporting on behalf of a minor, or for an adult that completed the activity/trip diary Individuals unavailable at the time of the interview Permitted Permitted Permitted Permitted Permitted Permitted Permitted Eligibility All household members No one under 18 All household members All household members Household members over five years All household members All household members All household members 16 years and over All household members Partial Response Definition Complete information from all employed household members; partial responses excluded from analyses Not defined Not defined Not defined Not defined Complete household responses except missing start and end of travel times Not defined Not defined Not defined Response Rate 26.2% 7.5% 37% 33% 33% 57% n/a n/a 36.8% Source: Adapted from Carr Smith and Corradino (2000a, 2000b)
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78 In the documentation of another study, it was stated that proxy reporting was permitted so as not to reduce the response rate and discard part of the sample; high levels of unit and item non-response were expected. However, it was found that proxy reporting led to an underestimation of trip rates by as much as 0.43 for males and 0.69 for females (Morpace International, 2003)
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79 household response to be considered complete. Thus, we may receive complete information for all adults in the 18-64 age group, receive information from only one adult in the over 75 age group, and obtain no information about adults in the 65-75 age group.
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80 to participate in the recruitment interview. Further analysis is conducted to determine the overall conversion of these soft refusals to complete household survey responses.
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81 2. The (implicit)
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82 5.5 D-7: ITEM NON-RESPONSE 5.5.1 Definition Item non-response has been defined as "the failure to obtain a specific piece of data from a responding member of the sample" (Zimowski et al., 1997a) , or the "failure to obtain ‘true' and complete data from each respondent" (Zmud and Arce, 2002)
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83 Broward Travel Characteristics Study 1996 702 13.2 not included In addition to the non-response on household income shown in Table 41, other items displaying high incidence of missing data in the seven data sets reviewed are driver license status of individuals (055 percent) , travel mode (0-26 percent)
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84 if the survey environment allows for this. In terms of non-contacts, there needs to be greater effort to contact the difficult to contact.
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85 questionnaire design, and easy to answer questions, thereby decreasing respondent burden (Axhausen, 1999)
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86 delivery in reducing unit non-response is very small (Dillman et al., 2001)
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87 Figure 7: Influences on the Likelihood of Contacting a Sample Household Source: Groves and Couper, 1998. According to Groves and Couper (1998)
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88 entire sample. Table 42 shows the number of call attempts made to convert households who were initially non-contactable22 for call history file 1.
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89 One-Person HHs 19% 29% 18% 23% 22% 27% Two-Person HHs 49% 48% 36% 23% 46% 35% One Worker 36% 40% 55% 23% 37% 40% Two Workers 34% 29% 45% 23% 33% 37% One Car 25% 38% 18% 23% 28% 33% Two Cars 51% 50% 55% 31% 49% 43% Three or more Cars 19% 10% 27% 46% 19% 19% Single Detached Dwelling 83% 74% 91% 85% 81% 74% Home Owner 81% 79% 60% 62% 79% 68% Mean Trips per HH 7.86 8.82 8.95 8.67 8.24 8.47 No Infants in Household (0-4yrs) 87% 92% 82% 92% 88% 87% No School Aged Children in HH 79% 79% 55% 77% 77% 72% One Adult Households 27% 35% 36% 23% 30% 31% Two Adult Households 60% 60% 45% 38% 58% 56% Income under $50,001 61% 68% 64% 50% 61% 62% Table 44 shows the differences in the mean number of trips for households converted from noncontacts to complete household surveys, from that for the entire sample.
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90 Calling non-responding households and reminding them to participate will be of no use if they have discarded or misplaced the survey package (Richardson, 2000)
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91 Total Trip Rates Not significantly different to responding households Mode Use Significantly higher walk and train trip rates than respondents The following section describes the non-response surveys developed by the Institute of Transport Studies (The University of Sydney) and Louisiana State University, and conducted by NuStats, as well as the data analyses.
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92 Independent samples of non-completers were drawn from the sample of telephone numbers that was generated for each of the four target household travel surveys. This study focused on two categories of non-completes: • Refusers: Those households that were contacted during the recruitment phase of the survey but refused to participate.
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93 frame) and 640 numbers were selected to represent the Terminator category (160 from each frame)
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94 to reaching a target number of completed interviews: 20 for the Terminator category and 10 for the Refuser category. Initially the CATI interviewing focused on Little Rock and was later expanded to all cities.
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95 Table 50: Response Rates for Terminator and Refuser Samples, Pilot and Main Survey Sample Size (Pilot) Complete (Pilot)
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96 refusers are more likely to respond to the extreme levels of post incentive offered. Table 54 shows that the majority of terminator and refuser non-respondents would answer the telephone if their caller-id displayed a research institute, university, or a government agency, confirming other reports (Kalfs and van Evert, 2003)
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97 1. Terminator results – this includes results of the multidimensional scaling; background information about the type of model used in the analysis of the Stated Choice data, and the results of the stated choice experiment; and 2.
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98 I didn't have the time to do it 19% 28% I travel too little to be of interest to you 34% 23% I didn't want to say no to the interviewer 35% 17% I don't do surveys 37% 17% I couldn't get other family members to take part 33% 26% I thought it was marketing deal or scam 37% 26% The person on the phone put me off 52% 13% I just couldn't be bothered to do it 28% 17% This was expected given that almost the same number of respondents also strongly agreed with these statements. Table 57 shows the results of cross-tabulations for the same statements, in terms of agreement and importance.
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99 goodness of fit of the model to the data.) Table 58 shows the results of the Euclidean Distance Model for the agreement statements.
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100 case, the model was asked to create a matrix with a maximum of four dimensions. Some stimulus coordinates in dimensions three and four were significant, hence this model was retained for analysis.
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101 • I didn't like the questions asked; and • I don't do surveys. In summary, the MDS for the terminator non-respondents showed that the following statements had positive values: respondents tended to agree with these statements rather than disagree, in relation to their decision not to participate in the original study.
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102 Who decides when the completed survey is returned Respondent chooses, interviewer chooses Who decides how the completed survey is returned Respondent chooses, interviewer chooses Length of survey Less than 10 mins, 10 – 19 mins, 20 – 29 mins, more than 30 mins Survey Features Green Survey Blue Survey Reward $1.00 Major prize draw Recruitment Method Telephone Telephone Survey conducted by: Government Private firm When completed survey is returned Interviewer chooses You choose How completed survey is returned You choose You choose Length of survey Under 10 minutes 10 to 19 minutes Would you be more likely to fill out the green or the blue survey? If you were given the survey you just checked, would you fill it out?
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103 where: ηjq = a random component with a zero mean and a distribution over individuals and alternatives dependent on the underlying parameters and observed sample data relating to alternative j and individual i. The ML model assumes a general distribution for ηij such that ηij can take on any number of distributional forms such as normal, lognormal, uniform, or triangular.
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104 Survey length (10-19 minutes)
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105 degrees of freedom) with a pseudo R2 of 0.12.
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106 No. of observations 1829† 1829† Constants only Log-Likelihood (β)
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107 that 57 percent of refusers stated that the reason for not responding to the Sydney Household Travel Survey was they were "Not interested/didn't want to" and 17 percent indicated that they "Had no time/ were too busy". The results are very different to the results shown in Table 63.
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108 You called me at a bad time 2% 34% 17% I don't do surveys 7% 23% 27% I didn't have the time to do it 2% 21% 26% I thought it was marketing deal or scam 2% 45% 11% The person on the phone put me off 20% 8% 18% I don't care about transportation issues 21% 7% 40% I just couldn't be bothered to do it 12% 21% 38% Multidimensional scaling analysis, using the ALSCAL procedure in SPSS®, was employed to determine whether the statements in terms of agreement could be grouped under "new" variables. Initially, the model was asked to create a matrix with a maximum of three dimensions.
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109 significant; hence, this model was retained for analysis. The stress and R squared values for the desired matrix are 0.00215 and 0.99996 respectively, depicting a good fit model.
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110 1. Higher levels of multiculturalism and multiple languages spoken within urban areas.
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111 4. Lurkers – view all of the questions but do not answer any questions; 5.
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112 member of the household 18 years of age or older?
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113 that no money will be solicited which distinguishes the call from telemarketing. In the actual 2001 NHTS, the introduction was changed to: "Hello, this is _____ and I'm calling for the U.S.
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114 any form of post-incentive. The transportation profession appears to remain generally unaware of this and post-1995 surveys have still offered post-incentives, and also offered non-monetary incentives.
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115 Incentives are clearly cost-effective, even when only modest gains are obtained in response rates. As an illustration, consider the following case.
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116 • "Reviewing instructions; • Using technology to collect, process, and disclose information; • Adjusting existing practices to comply with requirements; • Searching data sources; completing and reviewing the response; and • Transmitting or disclosing information." (OMB, 2004) Burden is estimated in terms of the "hour burden" that individuals expend in filling out forms, and in terms of the "cost burden" derived from electronic recordkeeping and reporting.
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117 • The respondent has greater influence in choosing the time (and perhaps the place) to complete the survey; • The survey topic or theme is important or relevant to them and/or their community; • The questionnaire design is as simple as possible, to minimize perceived difficulties (physical, intellectual, and/or emotional)
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118 household income, census data could be used to derive an expected income level for households within a defined geographical area.
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