Language Development and Enjoyment of Reading: Impacts of Early Parent-Child Activities in Two Growing up in Scotland Cohorts

Appendix A: Further details of explanatory and outcome variables

Social background variables

Parental level of education

At the first wave of data collection, each parent was asked to provide information on the nature and level of any school and post-school qualifications they had obtained. The information is updated at each subsequent contact. Qualifications are grouped according to their equivalent position on the Scottish Credit and Qualifications Framework which ranges from Access 1 to Doctorate. These are further banded to create the following categories: Degree-level academic or vocational qualifications, Higher Grades or equivalent vocational qualification ( e.g. SVQ 3), Upper-level Standard Grades (grades 1 to 4) or equivalent vocational qualification ( e.g. SVQ 1 or 2), Lower-level Standard grades (grades 5 to 7) or equivalent vocational qualifications ( e.g. Access 1 or 2, National Certificates). The highest qualification is defined for each parent and a household level variable is calculated. In couple families this corresponds to the highest classification amongst the respondent and his/her partner.

Equivalised annual household income

The income that a household needs to attain a given standard of living will depend on its size and composition. 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. "Equivalisation" means adjusting a household's income for size and composition so that we can look at the incomes of all households on a comparable basis.

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.

Other variables

Household variables

GUS data also contains information about the composition of respondents' household. This includes information about all adults and children who reside at the respondent's address at the time of interview, and information about how household members are related to each other - for example, whether children in the household are biological siblings. The following household variables were used in the analysis undertaken for this report:

• Whether child was first born: States whether the cohort child has any older siblings - 'Yes' (cohort was first born); 'No' (cohort child has older sibling(s)).
• Number of children in household: States the number of children living in the household at the time of interview, including the cohort child. For the purposes of this report, the number of children in the household was grouped into three categories: 'Four or more children'; 'Two or three children'; and 'One child' ( i.e. the cohort child is an only child).
• Family type: States whether the cohort child lives in a one-or two-parent household. Note that this variable makes no distinction between biological and non-biological parents/carers.

Languages spoken in household

At the first sweep of data collection, GUS respondents were asked whether English was the language usually spoken in the household and whether other languages were spoken - whether 'English only', 'English and other language(s)', or 'Other language(s) only'. At subsequent sweeps of data collection this information was updated in cases where a new partner had moved into the household.

Employment status

Details on respondents' and their partners' employment were collected at the first sweep of data collection and checked and updated at each subsequent sweep. In this report, variables have been derived which denote an individual's employment status as either 'Working full-time' (defined as 35 hours per week or more); 'Wokring part-time' (defined as less than 35 hours per ptweek), or 'Not working'.

Note that 'Partner's employment status' includes only cases where a partner is resident in the household at the time of the interview. Note also that respondents who were on maternity leave at the time of the 10 month interview have been classified as 'Not working'.