B. Life evaluation
The life evaluation module is not intended to be used in its entirety. To some degree, the measures it contains should be considered as substitutes for each other rather than as complements. Nonetheless, all of the measures included in the module add something over and above the basic satisfaction with life question contained in Module A. Broadly speaking, there are three groups of question contained in Module B.
The first two questions (the Cantril self-anchoring striving scale and the overall happiness question) are alternative measures of the same underlying concept as satisfaction with life. Although there is some debate as to whether the measures do indeed capture exactly the same concept (Helliwell, Layard and Sachs, 2012) or whether the Cantril scale is a more “pure” measure of life evaluation and overall happiness somewhat more influenced by affect (Diener, Kahneman, Tov and Arora, in Diener, Helliwell and Kahneman, 2010), there is no doubt that the measures are all predominantly evaluative. As discussed above, the Cantril scale is somewhat more awkwardly worded than the satisfaction with life question, but tends to produce a slightly wider distribution of responses (ONS, 2011) and has been thought to have a stronger association with income (Helliwell, 2008; Diener, Kahneman, Tov and Arora, in Diener, Helliwell and Kahneman, 2010). However, when the Cantril Ladder and life satisfaction questions are asked of the same respondents, they show essentially identical responses to income and other variables (Chapter 10 of Diener, Helliwell and Kahneman, 2010), so much so that an average of life satisfaction and the Cantril Ladder performs better than either on its own. Some authors have noted that the word “happiness” can be challenging to translate effectively (Bjprnskov, 2010; Veenhoven, 2008), and Bjprnskov further argues that life satisfaction is easier to translate more precisely. However, happiness may be easier to communicate to the public than the more “technical” satisfaction measures. Helliwell, Layard and Sachs (2012) note, based on analysis of the European Social Survey, that averages of overall happiness and life satisfaction perform better than either does alone in terms of the proportion of variance that can be explained by a common set of explanatory variables.
Some of these questions (B3 and B4) capture information on the respondent’s perceptions of prior life satisfaction and their anticipated future life satisfaction. This potentially provides some information about how optimistic or pessimistic the respondent feels, but it can also add information on the respondent’s overall life evaluation, as a person’s expectations of the future are part of how they evaluate their life. This view is reflected in the methodology for life evaluation used by the Gallup Healthways Well-being Index, which is calculated as the average of the Cantril scale and the anticipated Cantril scale 5 years in the future (Gallup, 2012).
Finally, the module includes the five questions (B5 to B9) that together define the Satisfaction With Life Scale (SWLS) developed by Ed Diener and William Pavot. The SWLS is one of the best-tested and most reliable multi-item scales of life evaluation. Since its development in 1985, the SWLS has accumulated a large body of evidence on its performance and has been tested in a number of different languages (Pavot and Diener, 1993). Because the SWLS is a multi-item measure, it has a higher reliability than single-item measures and is more robust to inter-personal differences in scale interpretation than they are. The SWLS adds value to the primary life evaluation measure in contexts where more space is available in a questionnaire, and where a more reliable measure of life evaluation would help interpret and calibrate the results from the primary measure.