Reaching the Cell Phone only Generation: The Behavioral Risk Factor Surveillance System Experience

1. Reaching the Cell Phone only Generation: The Behavioral Risk Factor Surveillance System Experience Michael Link1, Michael Battaglia2, Martin Frankel3, Larry Osborn2, and Ali H. Mokdad4 1 The Nielsen Company 2 Abt Associates 3 Baruch College, City University of New York 4 Centers for Disease Control & Prevention 2008 DC-AAPOR Meeting on Cell Phone Research, Washington, DC

2. Phone Shop Apocalypse II:The Plague of Cell Phones!!!

3. Conducting surveys via cell phones can be operationally challenging • Cell phone frame very inefficient • Cannot use autodialers for “cold calling” • Charges for incoming calls/minutes used • Safety concerns • Potential mode effects / measurement errors • Level of cognitive engagement

4. Behavioral Risk Factor Surveillance System (BRFSS) • Monthly state-based RDD survey of health issues and related risk factors • 50 states, District of Columbia, Puerto Rico, Guam, and Virgin Islands • 350,000+ adult interviews conducted in 2007 • Significant declines in participation overall, particularly among younger adults and males

5. 2007 BRFSS cell phone pilot • Conducted in Georgia, New Mexico, & Pennsylvania • Target: 200 cell & landline / 200 cell-only (per state) • 1,200 total interviews • Abbreviated BRFSS core interview: • 66 questions • 15-17 minutes (on average) • Post-paid (contingent) Incentives: • $10 for completing the detailed interview • $1 for completing only the screener

6. Screening questions • Introduction • Confirmed telephone number • Is this a cellular telephone? • Are you 18 years of age or older? • Are you a resident of (state)? • “Do you also have a landline telephone that is used to make and receive calls?” • Yes – took subsample of respondents • No – took all respondents

7. Survey Participation Rates

8. Cell Phone participation rates

9. Comparison of respondent demographics

10. Landline and Cell phoneframes & populations Landline Telephone Frame Cellular Telephone Frame Landline only (A) Landline & Cell phone (B, C) Cell phone only (D)

11. Percent male 51.1 46.0 37.9 38.2 Landline survey Cell phone survey State equalized design weight applied

12. Percent 18-34 years 51.4 24.0 14.5 19.6 Landline survey Cell phone survey State equalized design weight applied

13. Percent Hispanic 21.4 15.2 16.8 12.2 Landline survey Cell phone survey State equalized design weight applied

14. Percent black 15.0 15.8 9.3 7.5 Landline survey Cell phone survey State equalized design weight applied

15. Percent high school or less education 60.3 48.5 39.8 33.6 Landline survey Cell phone survey State equalized design weight applied

16. Percent married 69.8 62.0 49.5 32.0 Landline survey Cell phone survey State equalized design weight applied

17. Comparison of key survey estimates

18. Percent any kind of health care coverage 89.0 86.0 78.7 70.1 Landline survey Cell phone survey State equalized design weight applied

19. Percent not received care due to cost barrier 20.4 24.9 16.3 10.2 Landline survey Cell phone survey State equalized design weight applied

20. Percent currently smoke cigarettes 31.1 23.4 24.8 17.3 Landline survey Cell phone survey State equalized design weight applied

21. Percent ever tested for HIV 54.2 43.6 37.5 36.6 Landline survey Cell phone survey State equalized design weight applied

22. Percent binge drink past 30 days 28.7 21.1 15.5 11.0 Landline survey Cell phone survey State equalized design weight applied

23. Comparison of Survey Costs

24. Cost per Interview • Data collection costs only • Level of effort: • RDD = 9.1 calls/case • Cell = 3.3 calls / case • Response rate: • RDD = 43% • Cell = 26% • Interview length: • RDD = 25 minutes • Cell = 12 minutes $196 $74 $64

25. What have we learned? • Group with both landline & cell phone differ depending on the frame from which they were sampled • Mode effect? Response / nonresponse effect? Frame effect? • Cell phone only group differs significantly from landline group on some issue domains, but not others • Risk behaviors seem most problematic

26. What have we learned? • Cell phone & landline usage varies significantly across states • Makes use of national estimates for post survey adjustment problematic • Compared to landline surveys, cell phone surveys: • Have lower rates of response at the screener stage • Similar rates at the interview stage • Working residential rates lower, but not as bad as expected • Are considerably more expensive

27. Address Based Sampling (ABS)as a potential alternative • “Address Based Sampling” refers to the probabilistic sampling of addresses from a centralized database • Typically current discussions are focused on the USPS DSF • Offers an alternative means of sampling cell phone households • Does require initial contact via mail or in-person

28. Success in reaching cell only households using ABS designs

29. Contact:Michael LinkMichael.Link@Nielsen.comFor more information on BRFSS:www.cdc.gov/brfss