Making sense of patient priorities: applying discrete choice methods in primary care using 'think aloud' technique

Background. Delivering effective health care within limited budgets requires an understanding of patient priorities. Discrete choice experiments (DCEs) provide patients with choices, where each choice differs in terms of certain attributes (such as waiting times, quality of care). Although this technique has significant potential in examining priorities, its use raises practical and conceptual issues. This paper describes the development of a DCE evaluating patient priorities in primary care. Methods. Twenty patients completed a DCE using a 'think aloud' protocol, where they verbalized their thinking while making choices. The analysis examined their decision-making processes. Results. There was evidence that patients reinterpreted some attributes, and related some to others outside the task. The cost attribute was interpreted in a variety of ways, dominating some patients' decision-making, being seen as irrelevant by others and being interpreted appropriately by some. The deree to which patients exhibited trading in line with theoretical assumptions also varied. Some choices in the hypothetical task were restricted by their previous experience, but more frequently patients tested the boundaries of the task in ways which directly reflected the primary care context. Conclusion. Patient interpretation of the discrete choice task was varied and some went beyond the formal boundaries of the task to make their choices. This highlights the importance of piloting attributes, providing clear instructions about the task and developing models of patient decision-making so that responses can be interpreted correctly.