Purpose: The aim of this study was to develop and validate the Trust in Oncologist Scale (TiOS), which aims to measure cancer patients' trust in their oncologist. Structure, reliability and validity were examined.
Methods: Construction of the TiOS was based on a multidimensional theoretical framework. Cancer patients were surveyed within a week after their consultation. Trust, satisfaction, trust in health care, self-reported health and background variables were assessed. Dimensionality, internal consistency, test-retest reliability and construct validity were investigated.
Results: Data of 423 patients were included (response rate = 65%). After item reduction, the TiOS included 18 items. Trust scores were high. Exploratory factor analysis suggested one-dimensionality. Confirmatory factor analysis nevertheless indicated a reasonable fit of our four-dimensional theoretical model, distinguishing competence, fidelity, honesty and caring. Internal consistency and test-retest reliabilities were high. Good construct validity was indicated by moderate correlations of trust (TiOS) with satisfaction, trust in health care, willingness to recommend and number of consultations with the oncologist. Exploratory analyses suggested significant correlations of trust with ethnicity and age.
Conclusions: The TiOS reliably and validly assesses cancer patients' trust in their oncologist. The questionnaire can be employed in both clinical practice and future research of cancer patients' trust.