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Sample size for pre-tests of questionnaires

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Abstract

Purpose

To provide guidance regarding the desirable size of pre-tests of psychometric questionnaires, when the purpose of the pre-test is to detect misunderstandings, ambiguities, or other difficulties participants may encounter with instrument items (called «problems»).

Methods

We computed (a) the power to detect a problem for various levels of prevalence and various sample sizes, (b) the required sample size to detect problems for various levels of prevalence, and (c) upper confidence limits for problem prevalence in situations where no problems were detected.

Results

As expected, power increased with problem prevalence and with sample size. If problem prevalence was 0.05, a sample of 10 participants had only a power of 40 % to detect the problem, and a sample of 20 achieved a power of 64 %. To achieve a power of 80 %, 32 participants were necessary if the prevalence of the problem was 0.05, 16 participants if prevalence was 0.10, and 8 if prevalence was 0.20. If no problems were observed in a given sample, the upper limit of a two-sided 90 % confidence interval reached 0.26 for a sample size of 10, 0.14 for a sample size of 20, and 0.10 for a sample of 30 participants.

Conclusions

Small samples (5–15 participants) that are common in pre-tests of questionaires may fail to uncover even common problems. A default sample size of 30 participants is recommended.

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References

  1. Presser, S., Couper, M. P., Lessler, J. T., Martin, E., Martin, J., Rothgeb, J. M., et al. (2004). Methods for testing and evaluating survey questions. Public Opinion Quarterly, 68, 109–130.

    Article  Google Scholar 

  2. Converse, J. M., & Presser, S. (1986). Survey questions. Handcrafting the standardized questionnaire. Newbury Park: Sage Publications Inc.

    Book  Google Scholar 

  3. Backstrom, C. H., & Hursch-César, G. (1981). Survey Research (2nd ed.). New York: Macmillan Publishing Company.

    Google Scholar 

  4. Streiner, D. L., & Norman, G. R. (2003). Health Measurement Scales. A practical guide to their development and use (3rd ed.). Oxford: Oxford University Press.

    Google Scholar 

  5. Groves, R. M., Fowler, F. J., Couper, M. P., Lepkowski, J. M., Singer, E., & Tourangeau, R. (2004). Survey methodology. Hoboken NJ: Wiley.

    Google Scholar 

  6. Beatty, P. C., & Willis, G. B. (2007). Research synthesis: The practice of cognitive interviewing. Public Opinion Quarterly, 71, 287–311.

    Article  Google Scholar 

  7. DeVellis, R. F. (2012). Scale development. Theory and applications (3rd ed.). Los Angeles, Newbury Park: Sage Publications Inc.

    Google Scholar 

  8. Wild, D., Grove, A., Martin, M., Eremenco, S., McElroy, S., Verjee-Lorenz, A., et al. (2005). Principles of good pratice for the translation and cultural adaptation process for patient-reported outcomes (PRO) measures: Report of the ISPOR task force for translation and cultural adaptation. Value Health, 8, 94–104.

    Article  PubMed  Google Scholar 

  9. Patrick, D. L., Burke, L. B., Gwaltney, C. J., Kline Leidy, N., Martin, L., Molsen, E., et al. (2011). Content validity—Establishing and reporting the evidence in newly developed patient-reported outcomes (PRO) instruments for medical product evaluation: ISPOR PRO good research practices task force report: Part 2—Assessing respondent understanding. Value Health, 14, 978–988.

    Article  PubMed  Google Scholar 

  10. Sprangers, M. A., Cull, A., Groenvold, M., Bjordal, K., Blazeby, J., & Aaronson, N. K. (1998). The European Organization for Research and Treatment of Cancer approach to developing questionnaire modules: An update and overview. Quality of Life Research, 7, 291–300.

    Article  CAS  PubMed  Google Scholar 

  11. Fayers, P. M., & Machin, D. (2000). Quality of life. Assessment, analysis and interpretation. New York: Wiley.

    Google Scholar 

  12. Beaton, D. E., Bombardier, C., Guillemin, F., & Ferrsaz, M. C. (2000). Guidelines for the process of cross-cultural adaptation of self-report measures. Spine, 25, 3186–3191.

    Article  CAS  PubMed  Google Scholar 

  13. Blair, J., & Conrad, F. G. (2011). Sample size for cognitive interview pretesting. Public Opinion Quarterly, 75, 636–658.

    Article  Google Scholar 

  14. PASW statistics, version 18, Chicago, IL.

  15. Clopper, C., & Pearson, E. S. (1934). The use of confidence or fiducial limits illustrated in the case of the binomial. Biometrika, 26, 404–413.

    Article  Google Scholar 

  16. StatXact version 4. Cytel software, Cambridge, MA.

  17. Perneger, T. V., Kossovsky, M. P., Cathieni, F., di Florio, V., & Burnand, B. (2003). A randomized trial of four patient satisfaction questionnaires. Medical Care, 41, 1343–1352.

    Article  PubMed  Google Scholar 

  18. Cleopas, A., Kolly, V., & Perneger, T. V. (2006). Longer response scales improved the acceptability and performance of the Nottingham Health Profile. Journal of Clinical Epidemiology, 59, 1183–1190.

    Article  PubMed  Google Scholar 

Download references

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Authors and Affiliations

  1. Division of Clinical Epidemiology, University Hospitals of Geneva, 6 rue Gabrielle-Perret-Gentil, 1211, Geneva, Switzerland

    Thomas V. Perneger, Delphine S. Courvoisier & Angèle Gayet-Ageron

  2. Department of Community Health and Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland

    Thomas V. Perneger, Patricia M. Hudelson & Angèle Gayet-Ageron

  3. Division of Primary Care Medicine, University Hospitals of Geneva, Geneva, Switzerland

    Delphine S. Courvoisier & Patricia M. Hudelson

Authors
  1. Thomas V. Perneger
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  2. Delphine S. Courvoisier
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  3. Patricia M. Hudelson
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  4. Angèle Gayet-Ageron
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Correspondence to Thomas V. Perneger.

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Perneger, T.V., Courvoisier, D.S., Hudelson, P.M. et al. Sample size for pre-tests of questionnaires. Qual Life Res 24, 147–151 (2015). https://doi.org/10.1007/s11136-014-0752-2

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  • DOI: https://doi.org/10.1007/s11136-014-0752-2

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