caa a22 4500 606177736 CHVBK 20210128100753.0 cr unu---uuuuu 210128e20150101xx s 000 0 eng 10.1007/s11136-014-0752-2 doi (NATIONALLICENCE)springer-10.1007/s11136-014-0752-2 Sample size for pre-tests of questionnaires [Elektronische Daten] [Thomas Perneger, Delphine Courvoisier, Patricia Hudelson, Angèle Gayet-Ageron] 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. Springer International Publishing Switzerland, 2014 Questionnaires nationallicence Validity nationallicence Pre-tests nationallicence Power nationallicence Sample size nationallicence Cognitive interviewing nationallicence Perneger Thomas Division of Clinical Epidemiology, University Hospitals of Geneva, 6 rue Gabrielle-Perret-Gentil, 1211, Geneva, Switzerland aut Courvoisier Delphine Division of Clinical Epidemiology, University Hospitals of Geneva, 6 rue Gabrielle-Perret-Gentil, 1211, Geneva, Switzerland aut Hudelson Patricia Department of Community Health and Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland aut Gayet-Ageron Angèle Division of Clinical Epidemiology, University Hospitals of Geneva, 6 rue Gabrielle-Perret-Gentil, 1211, Geneva, Switzerland aut Quality of Life Research Springer International Publishing 24/1(2015-01-01), 147-151 0962-9343 24:1<147 2015 24 11136 https://doi.org/10.1007/s11136-014-0752-2 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 brief-communication jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11136-014-0752-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Perneger Thomas Division of Clinical Epidemiology, University Hospitals of Geneva, 6 rue Gabrielle-Perret-Gentil, 1211, Geneva, Switzerland aut NATIONALLICENCE 700 1- Courvoisier Delphine Division of Clinical Epidemiology, University Hospitals of Geneva, 6 rue Gabrielle-Perret-Gentil, 1211, Geneva, Switzerland aut NATIONALLICENCE 700 1- Hudelson Patricia Department of Community Health and Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland aut NATIONALLICENCE 700 1- Gayet-Ageron Angèle Division of Clinical Epidemiology, University Hospitals of Geneva, 6 rue Gabrielle-Perret-Gentil, 1211, Geneva, Switzerland aut NATIONALLICENCE 773 0- Quality of Life Research Springer International Publishing 24/1(2015-01-01), 147-151 0962-9343 24:1<147 2015 24 11136