Careful use of a range of tracking procedures and of tracking databases can be critical in locating respondents. In California and Colorado, as discussed above, the evaluators were handicapped from the start by delays between when enrollment in the demonstration began and when the survey began. In both California and Colorado, as soon as the survey organizations had the sample information, they sent out requests by mail for contact information to the address in the public assistance records. In California, UC- Berkeley offered a $5.00 incentive for returning the information. The response rate to this request was 30 percent in California and 18 percent in Colorado.
In California, for the Wave I survey, the UC-Berkeley Survey Research Center asked the county welfare departments to check their records on cases they were not able to locate; three of the four counties were able to comply with these requests. In addition, the Survey Research Center used directory assistance and address corrections from the post office, as well as the state Parent Locator system used for child support enforcement. For the Wave II survey, they did not use the Parent Locator system; by that time, however, they had on-line access to credit bureau and motor vehicle registration databases, as well as contact information obtained in the Wave I interview. They did not attempt to contact nonrespondents to Wave I.
In Colorado, the evaluator is relying largely on checks of state automated systems for the AFDC, Food Stamp, and child support enforcement programs, as well as on-line telephone directories. They sometimes have reviewed hard-copy case files for the names of friends or relatives. Although one progress report discusses obtaining credit bureau data, there is no indication this was implemented. The original Colorado survey plans indicated that on each successive wave they would only contact those who had completed the previous wave; this would lead to smaller samples sizes for later waves. There is no indication they have reconsidered this plan at this time, although use of better tracking methods could improve response rates on later waves.
The Wisconsin WNW work plan discusses only directory assistance and public assistance record checks. We have no information on tracking methods planned for the Michigan and Minnesota surveys. However, Abt Associates, who will conduct the Michigan survey, and RTI, who is conducting the Minnesota surveys, are experienced firms with access to a wide range of tracking methods. In Minnesota, MDRC staff reported that cases were tracked and interviewed throughout the state and sometimes even if they had moved to other states.