Content Validity and Test-retest Reliability of Self-reported Questionnaire Assessing Knowledge and Perception of SMS Thumb: A Cross-sectional Study

Introduction: Continuous texting is associated with more stress on the thumb, which may cause the onset of a variety of wrist and thumb conditions. Today's youth spend the majority of their time on smartphones, which might cause texting thumb symptoms to occur. As there is a lack of a questionnaire that can evaluate their awareness and views, this was the first study that develops as well as evaluates the validity and reliability of a self-designed questionnaire.<br />Aim: To assess the validity and reliability of a self-designed questionnaire that measured knowledge and perception of Short Message Service (SMS) Thumb.<br />Materials and Methods: This cross-sectional pilot survey was conducted in Mangalore, Karnataka, India from June 2022 to July 2022. Validity and reliability were performed in two sections. A panel of four experts reviewed the questionnaire's content validity to determine its Content Validity Index (CVI), while reliability was performed by using test-retest reliability method which was carried out through an online survey among 31 young individuals with the inclusion criteria of non medical students aged between 18-25 years. CVI was used to analyse the questionnaire's validity. Test-retest statistical analysis was performed by Statistical Package for the Social Sciences (SPSS Inc; Chicago, IL), Version 26.0 and internal consistency were used to assess the reliability. Pearson correlation was used to perform the reliability.<br />Results: The item Content Validity Index (i-CVI) of the questionnaire was 1.00 for 20 of the 25 questions, while the average scale CVI of the questionnaire was 0.95. Test-retest reliability and internal consistency were both evaluated using Cronbach's alpha coefficient and Pearson's correlation ratio, respectively. The questionnaire was significantly reliable with a p-value <0.05.<br />Conclusion: The questionnaire showed acceptable test-retest reliability and content validity which can be a useful tool for measuring awareness and attitude about SMS Thumb.