Derivation of a UK preference-based value set for the Short Warwick-Edinburgh Mental Well-being Scale (SWEMWBS) to allow estimation of Mental Well-being Adjusted Life Years (MWALYs)

•This is the first attempt to derive a preference-based value set for a generic mental well-being instrument.•The valuation responses supported the face validity and feasibility for the valuation of the SWEMWBS.•The Inverse Variance Weighting hybrid model is firstly applied in preference elicitation research.•Units of QALY gain and MWALY gain have different implications for economic evaluations of mental well-being interventions.•This study tests the use of remote-control function in videoconferencing during the interview.