Testing and validation

The multi-item well-being scales in NPC's Well-being Measure have undergone a thorough processes of testing, to ensure that they are reliable, valid and sensitive to change.

All of the scales have undergone tests to determine the following characteristics:

  • Internal consistency - a measure of correlation between different items in the same scale. It shows the extent to which individual questions in a scale are measuring aspects of the same underlying factor. Each scale achieves a score on Cronbach's Alpha of above 0.7.
  • Test-retest reliability - examines how stable results gathered using the scales are over time.
  • Sensitivity to change - tested by comparing mean scores using a paired samples t-test. Differences in mean scores are detected at 95% significance.
  • Predictive validity - the extent to which a score on a scale predicts a respondent's score on other measures of participant characteristics.
  • Face validity - a 'common sense' test of whether the scales appear to be a good measure, whether questions are appropriate and whether it behaves in way you might expect.

This process is described in detail in our report Feelings count, which you can download here. You can read a shorter paper on the process of validating the scales here.

You can see who was in involved in the process of developing the Well-being Measure here.

You can see all the well-being questions included in NPC's Well-being Measure by downloading the sample survey here.