1. 1 Impact of Changes in the Telephone Environment On RDD Telephone Surveys Mary Cay Murray Abt Associates Inc Erin Foster Abt Associates Inc Jessica Cardoni Abt Associates Inc Chris Becker Abt Associates Inc Paul Buckley Consultant Marcie Cynamon National Center for Health Statistics

2. 2 Changes in the Telephone Environment Topics: Out-of-scope lines Answering machines Privacy manager devices Do-Not-Call lists Database: The National Immunization Survey, (Q1/98-Q4/02)

3. 3 The National Immunization Survey (NIS) Data collection conducted quarterly since April of 1994 Sponsored by the National Immunization Program and the National Center for Health Statistics, both of the Centers for Disease Control and Prevention National studydata collection in 78 non-overlapping Immunization Action Plan (IAP) Areas: 50 states, 27 metropolitan areas, and the District of Columbia Yearly, 10 million telephone calls made to identify households with 35,000 age-eligible children

4. 4 NIS, Continued Measures vaccination coverage of children between the ages of 19 and 35 months 3,000,000 sample telephone numbers drawn per year List-assisted design Processed through GENESYS-IDplus ® before CATI screening 1,000,000 households contacted per year

5. 5 Growth in Out-of-Scope Lines Growth across Quarters Non-working Numbers by Census Division

6. 6 NIS: Estimated Out-of-Scope Percentages by Quarter

7. 7 Census Divisions

8. 8 NIS: Non-working Numbers by Census Division

9. 9 NIS: Non-working Numbers by Census Division – Q4/00 and Q4/02

10. 10 NIS: Answering Machines Next, we will examine the trends in the prevalence and use of answering machines.

11. 11 NIS: Percent Ever Answering Machine by Quarter

12. 12 NIS: Percent Finalized Answering Machines by Quarter

13. 13 NIS: Percent Finalized Answering Machines by Census Division by Quarter

14. 14 NIS: Percent Finalized Answering Machines by Census Division – Q1/00 and Q4/02

15. 15 Privacy Managers in the NIS What do we mean by Privacy Manager? A call-screening device that works with caller-ID to manage all incoming calls.

16. 16 Coding Rules for Privacy Manager Calls If the line rang with no answer by the household, but the interviewer identified the study when asked to do so by the Privacy Manager, the case is coded as PM ring-no-answer; If the Privacy Manager denied the call, the case is coded as a PM hang-up-during-introduction; If the call is sent to an answering machine, the case is coded as answering machine.

17. 17 NIS: Percent Identified Privacy Manager by Quarter

18. 18 NIS: Identified Privacy Manager by Census Division by Quarter

19. 19 NIS: Identified Privacy Manager by Census Division – Q2/01 and Q4/02

20. 20 NIS: Privacy Manager by Census Division, Log

21. 21 NIS: Identified Privacy Manager Outcomes

22. 22 State Do-Not-Call Lists These lists do not apply to surveys such as the NIS Telephone numbers on these lists are likely to be households Identified by Marketing Systems Group

23. 23 NIS: State Do-Not-Call Lists

24. 24 NIS: State Do-Not-Call Lists by Census Division – Q2/02 and Q4/02

25. 25 NIS: Final Outcomes of Do-Not-Call List Cases

26. 26 NIS Do-Not-Call List Maintained cumulatively since 1998 Telephone numbers can be sampled again across quarters in the NIS

27. 27 NIS Do-Not-Call List: Percent of Lines by Quarter

28. 28 Conclusions Increase in non-working numbers leads to fewer household lines in samples Answering Machines continue to be used to screen calls and increasingly to avoid participating in surveys Privacy Managers are growing, but still a small portion of total sample Cases on state do-not-call lists are generally cooperative Take me off your list is an easy way to opt out of a survey

29. Abt Associates Inc. mary_cay_murray@abtassoc.com