GROWING UP IN SCOTLAND: THE CIRCUMSTANCES AND EXPERIENCES OF 3 YEAR OLD CHILDREN LIVING IN SCOTLAND IN 2007/08 AND 2013

Appendix A: Details of key socio-economic variables

Household level equivalised income

In GUS, overall income is measured at household level before tax. At each interview, parents are asked to provide information about the amount of income they receive. This covers all sources of income including earnings, benefits, tax credits and interest from savings. Amounts can be given as either weekly, monthly or annual amounts which are adjusted to produce a single annual figure.

These figures are then 'equivalised' to reflect differences in household size and composition, as these factors affect the income level required to attain a particular living standard. For example, a couple with dependent children will need a higher income than a single person with no children to attain the same material living standards. The equivalised household income enables comparison between households of different size and composition. Furthermore, it also enables comparison over time and, in the case of GUS, between the two cohorts.

After equivalisation, the sample is split into five, equally-sized groups - or quintiles - according to income distribution. Each group thus contains around 20% of families. However, because the income data on GUS is collected in a series of ranges (e.g. £10,400 to £15,599, £15,600 to £20,799 and so on) rather than as a scale of specific, individual values (e.g. £12,457) the split can be slightly imprecise and some groups may contain slightly more or less than 20%. It is also important to note that the groups are split relative to the spread of income for that cohort and sweep of data collection rather than in reference to a fixed cut-off point. As such, the cut-off point denoting the maximum annual income of the poorest 20% of families in BC1 will be different to the cut-off point for the equivalent group in BC2. Nevertheless, in each cohort the lowest and highest quintiles will represent the richest and poorest 20% of families with a child aged 3.

Area deprivation (SIMD)

Area deprivation is measured using the Scottish Index of Multiple Deprivation (SIMD) which identifies small area concentrations of multiple deprivation across Scotland. It is based on 37 indicators in the seven individual domains of Current Income, Employment, Health, Education Skills and Training, Geographic Access to Services (including public transport travel times for the first time), Housing and a new Crime Domain. SIMD is presented at data zone level, enabling small pockets of deprivation to be identified. The data zones, which have a median population size of 769, are ranked from most deprived (1) to least deprived (6,505) on the overall SIMD and on each of the individual domains. The result is a comprehensive picture of relative area deprivation across Scotland.

In this report, the data zones are grouped into quintiles. Quintiles are percentiles which divide a distribution into fifths, i.e., the 20th, 40th, 60th, and 80th percentiles. Those respondents whose postcode falls into the first quintile are said to live in one of the 20% least deprived areas in Scotland. Those whose postcode falls into the fifth quintile are said to live in one of the 20% most deprived areas in Scotland.

Further details on SIMD can be found on the Scottish Government Website

http://www.gov.scot/Topics/Statistics/SIMD/BackgroundMethodology