Exploring the Utility of the Subtractive Approach to Quality of Life Importance Weighting

This paper seeks to contribute to two inter-related debates on the measurement of Quality of Life (QoL): 1. the utility of importance weighting, and 2. the appropriate translation of the ‘gap approach’ to QoL. While on the one hand scholars argue for the utility of importance weighting (e.g. Hsieh, 2016), others (like Wu & Yao, 2006) argue that it is unnecessary. Relatedly is the issue of an effective approach to weighting that is both methodologically robust and intuitive. The data analysed is a sample (n=970) from a wider study on qualitative approach to QoL measure development. Respondents were undergraduate students from various disciplines and levels of study at a university in Nigeria. A survey using a battery of instruments: the Student Quality of Life Scale (SQOLS), a new, 40-item measure of importance and satisfaction with achievement and the Satisfaction with Life Scale (SWLS), was undertaken. The SQOLS domains include material, status, relational and achievement, while the SWLS is a widely used measure of global life satisfaction. Drawing on the WEDQoL Group’s (Woodcock et al, 2009) approach, the analysis used an abridged, 3-point scale for satisfaction items and a 5-point scale for importance items. A composite SQOLS measure was created using the subtractive approach, in which the satisfaction scores were subtracted from the importance scores, following Roszkowski and Spreat (2010). The composite SQOLS domain scores and the SQOLS were positively correlated with the SWLS showing convergence. Based on the results, the paper argues that consistent with Hsieh (2016), importance weighting has utility and validity, especially in homogenous groups. Further, it argues for the further application and testing of the subtractive method, particularly in developing countries where people’s expectations often outweigh their ability to achieve them satisfactorily.