Introduction: In order to measure and assess various characteristics of individuals, in addition to psychometrics, it is important to design an instrument in the shortest form that is still valid. Given the widespread use of the 70-question lifestyle questionnaire, this study aimed to investigate the psychometrics and use of the shortened form of the 70-question lifestyle questionnaire.
Materials and Methods: This cross-sectional study was conducted on all secondary school teachers in Isfahan in 2024 (about 8000 people) using convenience sampling method. Considering the use of the standard and long form of the Laali’s Lifestyle Questionnaire (2012) with 10 scales, the face, content, concurrent, criterion (divergent and convergent) validity of the questionnaire was measured to obtain a shortened instrument. The data were analyzed by Pearson’s correlation coefficient and Student's t-test for independent groups.
Results: After applying the proposed modifications in the qualitative face validity stage, 22 items were removed from the questionnaire in the content validity determination stage and a 48-item form was presented. The internal consistency of the short form was confirmed with respect to the positive and significant correlation between the score of each item and the total score of the questionnaire (p≥0.01), except for item 37. When the 70-item form and the shortened form were administered simultaneously, the concurrent validity of the 47-item form was confirmed. Cronbach's alpha coefficient was calculated to be 0.91 for the shortened form and in the range of 0.718 to 0.819 for the questionnaire scales.
Conclusion: Given the widespread use of the 70-item lifestyle questionnaire in research, and the confirmation of the psychometric properties of the shortened form in this study, the use of the shortened form is recommended due to ease of response, time saving, and increased internal validity of the research.