In order to control the spread of COVID-19, people must adopt preventive behaviours that can affect their day-to-day life. People's self-efficacy to adopt preventive behaviours to avoid COVID-19 contagion and spread should be studied. The aim of this study was to develop and psychometrically test the COVID-19 prevention, detection, and home-management self-efficacy scale (COVID-19-SES). We conducted an observational cross-sectional study. Six-hundred and seventy-eight people participated in the study. Data were collected between March and May 2020. The COVID-19-SES' validity (content, criterion, and construct), reliability (internal consistency and test-retest reliability), and legibility were studied. The COVID-19-SES' reliability was high (Cronbach's alpha = 0.906; intraclass correlation coefficient = 0.754). The COVID-19-SES showed good content validity (scale's content validity index = 0.92) and good criterion validity when the participants' results on the COVID-19-SES were compared to their general self-efficacy (r = 0.38; p < 0.001). Construct validity analysis revealed that the COVID-19-SES' three-factor structure explained 52.12% of the variance found and it was congruent with the World Health Organisation's recommendations to prevent COVID-19 contagion and spread. Legibility analysis showed that the COVID-19-SES is easy to read and understand by laypeople. The COVID-19-SES is a psychometrically robust instrument that allows for a valid and reliable assessment of people's self-efficacy in preventing, detecting symptoms, and home-managing COVID-19.
Keywords: COVID-19; psychometrics; self-efficacy.