Studies of Welfare Populations: Data Collection and Research Issues. Incentives in Panel Studies

06/01/2002

Many studies of welfare leavers are panel studies  that is, they reinterview the same household, or the same respondent, more than once over a period of time. Assuring participation is especially important for panel studies because participation at baseline usually sets a ceiling for the retention rate over the life of the panel.(1)  For this reason, investigators often advocate using sizable incentives at the first wave of a panel study. An incentive experiment was carried out at Wave 1 of the 1996 Survey of Income and Program Participation (SIPP), a longitudinal survey carried out by the U.S. Census Bureau to provide national estimates of sources, amounts, and determinants of income for households, families, and persons. SIPP primary sample units were divided into three groups to receive $0, $10, and $20. James (1997) found that the $20 incentive significantly lowered nonresponse rates in Waves 1 to 3 compared with both the $10 and the $0 conditions, but the $10 incentive showed no effect relative to the zero-incentive group. Mack et al. (1998) reported on the results through Wave 6 using cumulative response rates, including an analysis of the effects of incentives on households differing by race, poverty status, and education in Wave 1. They found that an incentive of $20 reduced household, person, and item (gross wages) nonresponse rates in the initial interview and that household nonresponse rates remained significantly lower, with a cumulative 27.6 percent nonresponse rate in the $0 incentive group, 26.7 percent in the $10 group, and 24.8 percent in the $20 group at Wave 6, even though no further incentive payments were made. (The SIPP does not attempt to reinterview households that do not respond in Wave 1 or that have two consecutive noninterviews.) Differences between the $10 incentive and the no-incentive group were not statistically significant. A subsequent experiment with paying incentives in Waves 8 and 9 of the 1996 SIPP to all Wave 7 and 8 nonrespondents (Martin et al., 2001) found that both a $20 and a $40 prepayment significantly increased the response rate above that in the $0 group; there was no significant difference between the two incentive groups. (Differential responsiveness to incentives by respondents differing in economic status is discussed in the later section on Findings for Low-Income Populations.)

Research on the Health and Retirement Survey (HRS) suggests that respondents who are paid a refusal conversion incentive during one wave do not refuse at a higher rate than other converted refusers when reinterviewed during the next wave (Lengacher et al., 1995). Unlike the SIPP, all respondents to the HRS receive an incentive at each wave, but these are much lower than the refusal conversion payments.

In sum, although the evidence currently available is still quite limited, that which is available suggests that the use of incentives in panel studies to increase initial response rates, convert refusals, and reduce subsequent attrition can be quite effective. Moreover, although in this context it is often assumed that once incentives are paid one must continue to offer them in all subsequent waves of data collection, these studies suggest that the effects of incentives on nonresponse and attrition in panel surveys can be sustained, even when incentives are not paid in subsequent waves of the study.

View full report

Preview
Download

"01.pdf" (pdf, 472.92Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"02.pdf" (pdf, 395.41Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"03.pdf" (pdf, 379.04Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"04.pdf" (pdf, 381.73Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"05.pdf" (pdf, 393.7Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"06.pdf" (pdf, 415.3Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"07.pdf" (pdf, 375.49Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"08.pdf" (pdf, 475.21Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"09.pdf" (pdf, 425.17Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"10.pdf" (pdf, 424.33Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"11.pdf" (pdf, 392.39Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"12.pdf" (pdf, 386.39Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"13.pdf" (pdf, 449.86Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®

View full report

Preview
Download

"14.pdf" (pdf, 396.87Kb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®