Summaries of Address-Based Sampling Presentations at the AAPOR Annual Meeting (2009)

June 29, 2009

Comparing Random Digit Dial (RDD) and United States Postal Service (USPS) Address-Based Sample Designs for a General Population Survey: The 2008 Massachusetts Health Insurance Survey

Susan Sherr, David Dutwin, SSRS
Timothy Triplett, Doug Wissoker, Sharon Long, Urban Institute

In the summer of 2008, the Urban Institute and Social Science Research Solutions (SSRS) conducted the Massachusetts Health Insurance Survey (HIS) on behalf of The Massachusetts Division of Health Care Finance and Policy.  The goal of the Massachusetts HIS is to document health insurance coverage and access among Massachusetts residents.  In an effort to include cell-phone only households in the study, the 2008 HIS employed a dual-sample-frame design that combined a random-digit-dial (RDD) telephone sample and an address-based (AB) household sample.  In addition, the AB sample and the RDD sample were each divided into two strata:  (1) sample records with both an address and matching telephone number and (2) sample records with either a phone number (RDD) or an address (ABS), but not both.  Survey respondents could choose to complete the survey by telephone, web or mail.  A total of 4,910 interviews were completed across both sample frames.  In comparing results from the RDD and ABS samples, we found that:

The sample yield was better and more efficient in the ABS sample.  As a result, the cost per interview was lower with the ABS sample.

Almost half of all respondents52% of ABS respondents and 34% of RDD respondentscompleted the survey online.  The popularity of a web questionnaire helped keep overall survey costs low.

The ABS response rate (34.7%) was lower than RDD (42.0%).  However, there was no significant difference by sample frame or by mode in either breakoffs or incompletes.

8.5% of ABS respondents were from cell-phone only households, a figure that is close to the recent NIH estimate for Massachusetts.

Unweighted demographic characteristics of the ABS respondents were closer to American Community Survey population counts than was true for RDD respondents, indicating a reduction in coverage bias with the ABS.  Nevertheless, nonresponse bias among underrepresented groups was present in both sample frames.

We conclude that the ABS offered a number of advantages over the RDD sample, including interviews with cell-only households, better sample yields, and lower costs per interview.  The better coverage in the ABS sample results in smaller weights, which resulted in smaller design effects and less sensitivity in estimates of key variables due to weighting as compared to the RDD sample.

Link to presentation slides

Source: http://surveypractice.org/2009/06/29/abs-summaries/