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Procedures and Measures for Further Research 53 In most cases, these problems are completely avoidable with appropriate checks. CATI and CAPI surveys offer enormous potential for cross checks on data quality in real time as a survey progresses and, in most such surveys, at least limited cross-checks are usually programmed in. Anecdotal information and recent experience of some of the research team suggests, however, that cross- checks are not always built in to survey data-collection procedures or that they are built in, but overridden or ignored by interviewers. Because of time constraints, it was not possible to develop consistent procedures in this project for cross-checks that should be built in to CATI or other types of interviews or to develop stan- dardized procedures for checking data after they have been retrieved. In our opinion, future research should focus on two main tasks. First, there is a need to develop a general list of the vari- ous checks that should be included in any travel survey. In part, these would need to be based on the minimum question specifications already developed as part of this project (see Section 2.1.1). Second, once a list has been compiled, standards for cross-checks that can apply to CATI and CAPI surveys should then be developed. Based on the experiences of the team working on this project, some of the better known problems include the following: 1. Children below minimum driving age reporting a drive-alone trip; 2. Children below minimum working age reporting work activities and travel; 3. People failing to report trips back to home both during and at the end of the day; 4. People failing to include activities at a place in transit trips (e.g., waiting and transferring) in a time-use or full activity survey; 5. People who are not employed reporting trips to or from work; 6. People failing to report other family members who accompanied them on travel; 7. Head of household reporting being under the age of 16; 8. People reporting more workers in the household than adults; and 9. People reporting more adults or more children in the household than the total house- hold size. It is recommended that unprocessed data from recent surveys be reviewed to compile as com- plete a list of these types of problems as possible. Second, once a list has been compiled, standards for cross-checks that can apply to CATI and CAPI surveys should then be developed. To this end, it is recommended that available CATI scripts and programs be reviewed to determine that checks have been built in and to examine the effectiveness of these checks. Structuring the received data into a snapshot of the actual behavior of a person over the course of the survey day is likely to be a very productive way of detecting errors and illogical responses. In most instances, the same checks that would be appropriate in a CATI or CAPI survey can also be used in a non-computerized survey to review data as they are obtained on paper diaries or other media. This may not be possible in all sit- uations, however, and it is likely that some standards developed for CATI and CAPI surveys will need to be adjusted for application in paper-and-pencil interviewing (PAPI) and related surveys. 4.2.5 E-8: Days and Periods to Avoid Data Collection While there are unwritten conventions about days on which household surveys should or should not be undertaken, no specific guidelines exist on this issue. Most household travel surveys are con- ducted in the Spring and Fall, but in some areas of the South, Spring may be defined as beginning earlier in February or even mid-January once schools are back in session. Most surveys generally avoid Thanksgiving and New Year because of the perception that travel is abnormal at this time of the year. Similarly, there is usually an attempt to avoid the period from the end of May through the middle of August because people are taking annual vacations and schools are not in session. There are inconsistencies however on whether surveying should be temporarily suspended for such times as Spring Break (either for schools or universities), Columbus Day, and Presidents Day. In addi- tion to this, there is a more general issue that relates to whether data from just Fall or Spring, or a