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Perneger TV, Courvoisier DS, Hudelson PM, et al. Sample size for pre-tests of questionnaires. Qual Life Res. 2014;24(1):147-51doi: 10.1007/s11136-014-0752-2.
Perneger, T. V., Courvoisier, D. S., Hudelson, P. M., & Gayet-Ageron, A. (2015). Sample size for pre-tests of questionnaires. Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation, 24(1), 147-51. https://doi.org/10.1007/s11136-014-0752-2
Perneger, Thomas V, et al. "Sample size for pre-tests of questionnaires." Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation vol. 24,1 (2015): 147-51. doi: https://doi.org/10.1007/s11136-014-0752-2
Perneger TV, Courvoisier DS, Hudelson PM, Gayet-Ageron A. Sample size for pre-tests of questionnaires. Qual Life Res. 2015 Jan;24(1):147-51. doi: 10.1007/s11136-014-0752-2. Epub 2014 Jul 10. PMID: 25008261.
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Qual Life Res. 2015 Jan;24(1):147-51. doi: 10.1007/s11136-014-0752-2. Epub 2014 Jul 10.

Sample size for pre-tests of questionnaires.

Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation

Thomas V Perneger, Delphine S Courvoisier, Patricia M Hudelson, Angèle Gayet-Ageron

Affiliations

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

PMID: 25008261 DOI: 10.1007/s11136-014-0752-2

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.

References

  1. Spine (Phila Pa 1976). 2000 Dec 15;25(24):3186-91 - PubMed
  2. Med Care. 2003 Dec;41(12):1343-52 - PubMed
  3. J Clin Epidemiol. 2006 Nov;59(11):1183-90 - PubMed
  4. Qual Life Res. 1998 May;7(4):291-300 - PubMed

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