1. Want to be an Early Bird? Can encouraging respondents to contact interviewers to make appointments increase co-operation and save costs? Matt Brown and Lisa Calderwood Centre for Longitudinal Studies Sub-brand to go here CLS is an ESRC Resource Centre based at the Institute of Education GSS Methodology Symposium – 27 th June

2. Context Survey costs increasing (Stoop, 2005) Increased focus on cost-effectiveness Main element of survey costs is fieldwork Experiment conducted to attempt to reduce fieldwork costs by encouraging respondents to initiate contact with interviewers to arrange appointments

3. Background “Early Bird” innovation pioneered by National Longitudinal Studies – 1979 cohort Respondents sent letter 2 weeks prior to fieldwork inviting them to call free telephone number to arrange appointment for interview. W22 (2004): $60/$80 incentive paid if telephoned within 4 weeks of receiving letter (+ standard incentive ($40) for completing interview). 49% took up offer Some impact on response rates: 80% overall 83% amongst those offered Early Bird Big impact on fieldwork effort: 3 hours to complete interviewing for Early Birds 5 hours to complete interviewing for ‘non’ Early Birds

4. Research questions Can this approach be successful on longitudinal studies in the UK context? –Incentives typical in household panel surveys but usually much lower value than US. Can sample members be motivated to be ‘early-birds’ without a financial incentive? –Incentives unusual in cohort studies in the UK –Appeal to ‘helping’ tendencies (Groves, Cialdini and Couper, 1992) –Increasingly consumer-drive, time-poor society

5. UKHLS Understanding Society: UK Household Longitudinal Study (UKHLS) 40,000 households Experiment conducted on the ‘Innovation Panel’ – 1500 households Develop and evaluate methodologies for longitudinal data collection Open call for proposals to carry out experimental designs in a longitudinal context A unique resource for methodological research.

6. Experiment design Group TreatmentN EB offer with incentive Additional £5 incentive paid to all household members who completed an interview (standard incentive £5 or £10) 347 EB offer – no incentive Appeal for help366 Control – no EB offer No request to contact interviewer in advance375

7. Implementation Two treatment groups sent letter three weeks before fieldwork –Next wave of study about to begin –“Opportunity to request an Early Bird Appointment by contacting interviewer on their mobile phone to arrange your interview at a time that suits you”. Also sent a leaflet “Want to be an Early Bird?” which explained the offer (identical other than mention of incentive or appeal) Given two weeks to contact interviewer to book an appointment for any date within first 4 weeks of data collection. (Interviewers all issued with mobile phones). Control group just sent letter

8. Results Take-up of offer Impact on response rate Impact on fieldwork efficiency

9. Results – take-up of offer Contacted interviewer Made and kept appointment N%N%Base EB Offer – Incentive 4011.53610.4347 EB Offer – No incentive 246.6215.7366 Any Early Bird Offer 649.0578.0713

10. Results – Response Rates Productive interviews N%Base EB Offer EB Offer – Incentive 26676.7347 EB Offer – No incentive 28577.9366 Any Early Bird Offer 55177.2713 Control group – No EB 27473.1375

11. Results – Impact on fieldwork effort MeanMaxSt. DevN EB Offer taken up EB Offer – incentive 1.3740.7336 EB Offer – no incentive 1.4551.021 All taking up offer 1.4050.8357 EB Offer not taken up EB offered –incentive 3.49142.29231 EB offered – no incentive 3.41212.04265 EB not offered 3.44132.04274 All not taking up offer 3.45212.12770 All 3.31212.12825 Number of interviewer visits to complete all interviewing

12. Results – Impact on fieldwork effort MeanSt. DevN EB Offer EB Offer – incentive 3.102.29347 EB Offer – no incentive 3.212.15366 Any EB offer 3.162.22713 Control group – no EB offer 3.372.22375 Total Number of Interviewer Visits – All issued households

13. Early Bird Characteristics Early BirdsNon-Early Birds Sig. Individual Average age58.048.8*** Sex (% Female)74.152.0*** Economic activity status (% Retired)41.425.0** Household Average size2.22.5- Children in home (<15) (%)18.223.6- 13

14. Low take-up rates: –Small incentive – in absolute terms? –Small increase in incentive relative to standard incentive? –Poor marketing? Emphasis on the term ‘Early-Bird’? –Materials not read –Mode effects – Face to face vs telephone? –Panel loyalty? Take-up rate significantly higher if incentive offered –Appeal to ‘helping tendencies’ unsuccessful? –More emphasis on how beneficial to the respondent? 14 Summary and Conclusions

15. 15 Summary and Conclusions When taken up EB leads to big reduction in interviewer visits needed to fully complete a case (as per NLSY) Low take-up means little impact on overall fieldwork effort Need to boost take-up rates Higher incentive rates? Better marketing of the EB offer?

16. Groves, R.M., Cialdini, R.B. and Couper, M.P. (1992). Understanding the decision to participate in a survey. Public Opinion Quarterly, 56, 475-495 Stoop, I. A. L. (2005). The Hunt for the Last Respondent: Nonresponse in sample surveys. The Hague: Social and Cultural Planning Office. 16 References