General practitioners' views on key factors affecting their desired income: A principal component analysis approach.

Based on the target income hypothesis, the economic behavior of physicians is mainly affected by their target income. This study aimed at designing an instrument to explain how general practitioners (GPs) set their desired income. A self-administered questionnaire of affecting factors on GPs' target income was extracted from literature reviews and a small qualitative study. Respondents were 666 GPs who completed the questionnaire (response rate= 52%) during 2 seasonal congresses of Iranian GPs. The principal component analysis (PCA) with varimax rotation was used to classify the variables and data reduction. Sample adequacy test, sphericity test, eigenvalues of components, and scree plot were evaluated for PCA. Cronbach's alpha was also checked to assess the internal consistency of the principal components. The results of the KMO measure of sampling adequacy (0.657) and Bartlett's test of sphericity (809.05, p<0.001) revealed that the collected data were suitable for PCA. Based on the scree plot pattern and eigenvalues greater than 1, 6 components including perceived comparative income, importance of responsiveness to patients, perceived socioeconomic status, economic expectations, socioeconomic status of paternal family, and provision of luxury services were selected, which explained 65.19% of the total variance. Finally, only those with a Cronbach's alpha value higher than 0.6 were considered reliable (the first 4 components). Based on the target income hypothesis, a physician's desired level of income affects their behavior. Our developed instrument and its mentioned components can be used in future studies related to GPs' behavior, especially those studies related to the economic aspects of GPs' behavior. It also helps formulate a better payment mechanism for primary care providers.