Adaptation or Scale-Norming? Theory and Preliminary Evidence on the Challenges of Interpreting Life Satisfaction Scale Data

Research into “evaluated wellbeing” in the subjective well-being (SWB) literature is typically conducted using life satisfaction scales. The majority of SWB scholars take the data these scale questions produce at face value and interpret what they see therein as “strong adaptation”. This is the idea that people rapidly acclimatise to shocks to their life satisfaction and return to a baseline or “set-point” level of life satisfaction. This paper presents an alternate interpretation: people “scale-norm” in response to shocks. This means that they use qualitatively different scales to respond to life satisfaction scale questions in different waves of a survey. Scale-norming can make responses to different scale questions neither inter-personally nor inter-temporally comparable, even ordinally. This paper presents a theoretical exposition of scale-norming in the context of life satisfaction research and reviews existing empirical evidence of its existence. It then presents results from two studies (N1 = 277; N2 = 1050) using a novel life satisfaction metric designed to identify scale-norming in life satisfaction scale responses. Results from both studies suggest that scale-norming does in fact plague life satisfaction scale questions, and further, that our understanding of adaptation may be significantly biased by our inability to account for such normalisation.