Data Collection With Surveys

1. Unit 2: Describing Transit Systems with Data Data Collection With Surveys

2. Outline • Types of surveys • Methods of sampling • Survey content • Survey instruments • Data collection plan

3. Last time we discussed the type of information we collect. Now, let’s discuss how we go about collected detailed survey data. Types of Surveys

4. Types of Surveys • Longitudinal survey • Over time • Cross-sectional survey • Single point in time

5. Survey Modes • On-board/Intercept • Telephone • Mail • Web-based • Smartphones (emerging)

6. On-Board & Intercept Surveys Overview Pros & Cons Easy to administer Inexpensive Relatively high response rates (33%-67%*) Constraint of trip time on length of survey instrument (mail-back option) Non-riders excluded • Conducted on-board vehicles, in stations or at stops • Target (study) population is current riders • Very common: 96% of transit agencies conducted on-board surveys between 2002-2004*

7. On-Board Survey Example

8. Telephone Survey Overview Pros & Cons Riders and non-riders Medium to long survey instruments Good response rates Interviewer training (Computer Aided Telephone Interviewing, or CATI, can help) Respondent needs a (local) telephone • Sampling frame is the household • Often use Random Digit Dialing (RDD) • Most common in cities with high use of transit • 71% of transit agencies conducted telephone surveys between 2002-2004*

9. Mail Survey Overview Pros & Cons Riders and non-riders Longer survey instruments Easy to administer Eliminates interviewer bias Response rates can be very low; typically below 20%* Usually not used for origin-destination surveys • Sampling frame is the household • Somewhat common • 38% of transit agencies conducted mail surveys*

10. Web Survey Overview Pros & Cons Very inexpensive Very easy to administer Longer survey instruments Eliminates interviewer bias Data already coded Respondent needs to have internet Difficult to achieve random sample • Sampling frame is riders (usually) • Increasingly common • 44% of transit agencies conducted mail surveys between 2002-2004*

11. Smartphone Survey Overview Pros & Cons Geocoded travel information Longer survey instruments Relatively easy to administer Data already coded Respondent needs to have a smartphone Difficult to achieve random sample Privacy concerns • Native smartphone applications can be used for travel surveys • Geocoded travel information supplemented with survey questions • Still in research & development • Some state DOTs; limited (if any) use in transit

12. Methods of Sampling

13. Methods of Sampling • Simple Random Sampling • Systematic Sampling • every nth unit selected • Stratified Sampling • divide the population into homogenous groups (e.g. areas of the city) • Cluster Sampling • natural groups, sample within groups • Probability Proportionate to Size • selection probability proportional to size

14. Sample Size Determination • Depends on the population size (e.g. number of riders) and the level of precision desired • Increase sample size  increase costs • Example for Simple Random Sampling

15. What is commonly included in transit surveys? Survey Content

16. Research Goals & Content • Origin & Destination Surveys • “This trip”: Origin, destination, purpose, access mode, egress mode, etc. • General Travel Behavior • Frequency of travel, how long using transit, alternative modes • Demographics • Gender, age, race, driver’s license, HH income, HH size, employment status • Satisfaction • Attributes of service: timely service, speed of service, cleanliness, comfort, safety, crowing, information • Other • Fare payment, new technologies, communications, etc.

17. Translating Research into Survey Questions

18. How to write a good survey Survey Instrument

19. Types of Questions • Closed-Ended • Dichotomous (2 answers, e.g. Yes/No) • Nominal (Categorical) • Ordinal (a.k.a. Likert, Ranking) • Filter/Contingency (Qualified) • Partially-Closed • Last answer is “Other______” • Open-Ended

20. Do’s and Don’ts • Questions should be: • Concise (multiple choice) • Understandable • Useful • Exhaustive • Questions should NOT be: • Double-barreled • Double negative • Technical jargon • Long-winded • Redundant • Obtrusive or embarrassing

21. Now, its time for you to practice In-Class Exercise

22. Putting it all together in order to create a… Data Collection Plan

23. Creating a Data Collection Plan • Determine research goals • Select survey mode & sampling methodology • Determine necessary sample size • Create detailed sampling plan • Draft questionnaire • Pre-test the questionnaire • Conduct staff training • Distribute survey & revise sampling plan • Code/process data & error check

24. Other Considerations • Language • English & Spanish • Special groups • Those who cannot read/write • Longitudinal comparisons • Consistency of questions with prior transit surveys

25. What does a (good) transit survey look like? Chicago Transit Authority

26. 2003 Chicago Transit AuthorityCustomer Satisfaction Survey • Objective: Comprehensive review of customer satisfaction conducted every 2 to 3 years • Content Included: • General travel behavior (modes, trip purpose) • Satisfaction with service delivery attributes • Loyalty towards CTA • Technology use (internet access, CTA website) • Fare payment • Demographics

27. CTA: Mode & Sampling • Mode: Household Telephone survey • Random Digit Dialing • Computer Assist • Stratified Sampling • Area of residence (N, S, NW, SW, W, Suburbs) • Mode (rail or bus) • Sample Size • Minimum of 200 respondents per strata • Total of 2,577 responses

28. CTA: Questionnaire • Question types • Mostly closed-ended questions (scales typically 5 points) • A few partially closed (other) & open ended questions • Interview length • Average of 21.4 minutes to complete • Pre-tested to assure length • Response rate • 64,986 telephone numbers attempted

29. CTA: Results • Satisfaction with bus service: • Has improved terms of reliability, information services, and comfort, among other things. • Has decreased in regards to access to service, personal safety, and intramodal transferring (within CTA). • Satisfaction with rail service: • Has improved or stay constant in terms of operator attributes (personnel), information sources, reliability and fare payment, among other things. • Has decreased in regards to access to service, intramodal travel, personal safety, and appearance.

30. CTA: Results

31. Conclusion • Surveys are a good way for agencies to know who their riders are and what they want. • There are several survey types with varying costs, penetration and bias. They should be chosen to match their target. • Surveys should be easy to understand and should encourage participants to complete them.

32. Reference Materials in this lecture were taken from: • Schaller. “On-board and Intercept Transit Survey Techniques”. Transit Cooperative Research Program Synthesis 63, National Research Council, Washington, DC (2005). • CTA, Customer Satisfaction Survey, 2003.