PURPOSE: To understand how the communication of risk in a discrete choice experiment (DCE) affects respondents’ decision making heuristics and strategies.
METHOD: A pilot DCE was designed to understand the preferences of female members of the public (recruited by posters in local cafes) for a breast screening programme described by three attributes (probability of detecting a cancer, risk of unnecessary treatment, and out-of-pocket cost) each with four levels. Two survey styles were used that varied how the risk attributes (probability of detecting a cancer and risk of unnecessary treatment) were presented as: (1) a percentage or (2) a percentage and icon array. Two approaches were used to understand how, and if, these risk communication methods affected respondents’ decision making strategies: eye-tracking and retrospective think aloud cognitive interviews. Eye-movements were recorded as a series of co-ordinates 1,000 times a second. Eye-tracking data were analysed in terms of direction of motion and total visual attention (dwell time) to pre-defined areas of interest using descriptive statistics. Immediately after completing the last choice question, respondents were asked a series of debriefing questions. The effect of each attribute on the women’s preferences were analysed using a conditional logit model.
RESULT: Twenty female members of the public completed the DCE and fifteen completed the DCE in the eye-tracking experiment. Respondents gave significantly more visual attention, indicating information processing, to both risk attributes when risk was communicated with an icon array rather than solely as a percentage with a mean dwell time of 6316 and 5043 milliseconds, respectively. Respondents to the icon array version also exhibited significantly more upwards and downwards eye-movements (43% v 38% of saccades) suggesting calculations were made in line with expected utility theory possibly reflecting a greater understanding of the risk information. The eye-tracking data confirmed the self-reported attribute non-attendance as stated by respondents when asked the de-briefing questions with significantly lower (by almost 70%) mean dwell times to these attributes. The results of the conditional logit revealed both probability of detecting a cancer and the risk of unnecessary treatment were significant in women’s decision to partake in breast screening.
CONCLUSION: This pilot study demonstrates that eye-tracking can be used as a method to further understand DCE responses. The pilot study also highlights the impact attribute framing can have on respondents’ decision making strategies and choices.
