Measuring poverty efficiently using adaptive deprivation scales

Deprivation scales are becoming increasingly familiar in research and in official statistics on poverty. They have been included in a number of UK surveys, including the Family Resources Survey, the Scottish Household Survey and the UK Household Longitudinal Study, for example. The full PSE scale is quite time consuming to administer so these surveys use a shortened version, only ask a sub-sample of people and/or don’t ask the questions in every wave.

Adaptive scales are a potential way to collect the same information more efficiently. That would help reduce survey costs and the burden on respondents, and make it easier to expand coverage to full samples and to include deprivation measures in a wider range of surveys.

Adaptive measures take advantage of the fact these scales are based in part in Item Response Theory. This shows that we can maximise the information collected for a given amount of survey time by screening respondents on the basis of initial answers, and halting questioning where it is very unlikely any further information will be gathered. The key issues are therefore: how much time can we save and how much information will we lose? Once we understand the trade-off, a policy decision can be taken about whether the balance is acceptable for a given set of intended uses.

This paper illustrates various implementations of adaptive deprivation scales using data from eight years of the UK’s Family Resources Survey (FRS). Results show that an adaptive approach collects more than 99 per cent of the information from the existing UK official deprivation measure in half the survey time. In addition, the paper suggests improvements in the design of the UK’s official deprivation scale as well as lessons for the development of future scales more generally.

Contact Nick Bailey (nick.bailey@glasgow.ac.uk) for more information.