Dear Editor,We read the article by Ohara et al. with great interest. Although the results were very interesting, there is an important methodological issue that needs to be raised in order to avoid misinterpretation.The authors developed and validated the Geriatric Self‐Efficacy Scale for Oral Health questionnaire on the same dataset. Here, is it crucial to emphasize that developing and validating a questionnaire on the same dataset can lead to over optimistic estimates of validity of the questionnaire. In other words, estimates of validity of the questionnaire might suffer from an overfitting problem; that is, performance of the questionnaire is well described only for the observed data, but its performance is still not valid for new and independent subjects. Split sampling is a commonly used method for questionnaire development and validation so that the dataset is split into two parts, one part for developing and the other for validation. In other words, in one part of the dataset the construct of the questionnaire will be identified by exploratory factor analysis, and in the reminder, its validity will be tested by confirmatory factor analysis. The authors recruited a remarkable sample size (n = 646 Japanese older people) for the study; however, we are wondering why the authors did no attempt to split the dataset and to determine the validity of the Geriatric Self‐Efficacy Scale for Oral Health questionnaire in the proper way.A take home message for readers is that questionnaire development and validation on the same dataset is a common mistake in biomedical research.AcknowledgementThis work was not supported by any organization.Disclosure statementThe authors declare no conflict of interest.ReferencesOhara Y, Yoshida N, Kawai H et al. Development of an oral health‐related self‐efficacy scale for use with older adults. Geriatr Gerontol Int 2017; 17: 1406–1411.Barke A, Bleichhardt G, Rief W, Doering BK. The Cyberchondria severity scale (CSS): German validation and development of a short form. Int J Behav Med 2016; 23: 595–605.Duarte C, Pinto‐Gouveia J, Ferreira C, Silva B. Caught in the struggle with food craving: development and validation of a new cognitive fusion measure. Appetite 2016; 101: 146–155.Norris J, Carpenter JG, Eaton J et al. The development and validation of the Interprofessional attitudes scale: assessing the Interprofessional attitudes of students in the health professions. Acad Med 2015; 90: 1394–1400.Sum RK, Ha AS, Cheng CF et al. Construction and validation of a perceived physical literacy instrument for physical education teachers. PLoS One 2016; 11: e0155610.Ayubi E, Mansori K, Khazaei S. Translation, adaptation, and validation of Hindi version of the pain catastrophizing scale: statistical issues of confirmatory factor analysis to avoid misinterpretation. Pain Med 2017; 18: 390–391.Safiri S, Ayubi E. Validity and reliability of the Greek version of the xerostomia questionnaire in head and neck cancer patients: methodological issues to avoid misinterpretation. Support Care Cancer 2017; 25: 2363.Safiri S, Ayubi E. Linguistic and psychometric validation of the Malaysian version of diabetes quality of life‐brief clinical inventory (DQoL‐BCI): methodological issues to avoid to misinterpretation. Res Social Adm Pharm 2017; 13: 398.
Geriatrics & Gerontology International – Wiley
Published: Jan 1, 2018
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