Development and internal validation of an instrument to measure the motivation of residents for family medicine

Background For several decades, medical school graduates' motivation to specialise in family medicine is decreasing. Therefore, residents in family medicine must be motivated for the profession and finish their residency. Objectives Goal of the current study is the development and internal validation of an instrument to measure the residents' motivation for family medicine, which is based on the self-determination theory: STRength mOtivatioN General practitioner (STRONG). Methods We used an existing instrument, the 'Strength of Motivation for Medical School,' adapted the 15 items and added a 16th item to make it suitable for residency in family medicine. After a review by experts, the questionnaire was sent to 943 residents of family medicine in Bavaria, Germany, in December 2020. An exploratory factor analysis for the STRONG item scores was carried out. The items were analysed for grouping into subscales by using principal component analysis. Cronbach's alpha for internal consistency was determined for calculating the reliability of the subscales. Results After analysis, the questionnaire appeared to consist of two subscales: 'Willingness to sacrifice' (eight items, Cronbach's alpha is 0.82) and 'Persuasion' (five items, Cronbach's alpha is 0.61). The factor analysis with Promax rotation resulted in two factors explaining 39.6% of the variance. The Cronbach's alpha of the full scale is 0.73. Conclusion Based on the internal validation, the STRONG Instrument appears to have good reliability and internal validity, assuming a two-factor structure. This may therefore be a helpful instrument for measuring the strength of the motivation of (future) family medicine residents.