METHODS: We conducted a systematic review to identify psychological constructs affecting the construction and heterogeneity of PP. A list of motivational factors for identifying and selecting psychological constructs to be measured in PP studies was also developed.
RESULTS: A total of 29 constructs were detected and categorized in these six categories: 1) cognition, 2) motivation, 3) individual differences, 4) emotion and mood, 5) health belief and 6) well-being and social support. Based on the strength of available evidence, these constructs were categorized into three class of recommendations: 1) Class I: constructs that should be measured in PP studies; 2) Class II: constructs that are reasonable to be measured in PP studies; 3) Class III: constructs that are not yet reasonable to be measured in PP studies. To help stakeholders to select psychological constructs relevant to their specific aim, the constructs were organized into 1) Constructs that may explain PP heterogeneity; 2) Constructs that may influence the formation process of preferences.
CONCLUSIONS: Understanding PP heterogeneity is important for both product development and evaluation. This study indicates which psychological constructs influence PP and how healthcare stakeholders can measure them in PP studies. This work received support from the EU/EFPIA Innovative Medicines Initiative  Joint Undertaking PREFER grant n 115966.