What's the issue?
The socio-economic and socio-ecological backgrounds of children and their families are very complex: they are constituted by an interaction of the different aspects and settings of the families' daily life (e.g. neighbourhood, family styles like single parent families, interrelation between family members, family income, and so on) (Paus-Hasebrink & Bichler, 2008).
It is clear that children's access to, and use of, the internet and online technologies differs according to their socio-economic status (SES). Yet this is difficult to measure and, as so often, varies by country, academic discipline, and research method (especially, whether one is interviewing parents or children). Since inequalities are crucial to internet research, it is important that researchers undertake this task and do not omit measuring SES in their research design. Qualitative and quantitative methods may approach this issue differently.
Several approaches are possible:
Sample children according to schools. It is generally possible to identify schools in poor, average, and well-off neighbourhoods on the basis of official statistics. It is accepted practice to assume that children from these schools will differ systematically by SES (although this assumption should not be made for individual children).
Ask children for information that will indicate, approximately, their SES. Teenagers may be expected to know how much education their parents received (below high school, finished high school, further education, university) although younger children may know if they went to university or not. This provides a fair proxy for SES.
Use proxy measures. The International Association for the Evaluation of Educational Achievement (IEA) survey developed two measures to estimate SES in their 2003 survey, namely: "About how many books/cars are there in your parents' or caretakers' home?" (Torney-Purta, Lehmann, Oswald, & Schulz, 2001). These questions provide fair proxies for educational and economic resources, respectively, and the answers are sufficient to sub-divide children by SES, though the measures are inexact.
Ask parents directly for information that will indicate SES. In some countries, terminal age of education is asked; or one may ask household income (by income brackets centred on the national average income and with more categories below the average than above). Or one may ask questions about occupation, etc according to a standard system of classification. This means either interviewing the parents, or sending a questionnaire to parents when interviewing their child (most efficiently, this can accompany the parental consent form, which must in any case be returned signed to the researcher).
Pitfalls to avoid
Don't ask children what their parents do for a living: first, one must hand code the answers, which is very time-consuming; second, the answers will be ambiguous (does an 'engineer' service the central heating or design bridges?, what does 'works in an office' mean?); third, many children do not know the answer. These questions may also result in social desirability biases, as children may feel uncomfortable saying their parents have low education or no car.
Examples of good practice
In our research, questions like age and place of birth, and questions regarding SES (such characterisation can consider the parents' level of education, type of job, economic sector and position, income, etc) were complemented with a questionnaire to the parents, which also included one open question regarding their opinion on the provision of public television for children. Both questionnaires were given a code number so that they could be matched in order to characterise the family unit. (Sofia Leitão, Portugal)
In the UK, market researchers ask a standard series of questions in order to classify people. Socio-economic status is strongly correlated with measures of parental occupation, education and income. In the UK Children Go Online research, parents were asked a series of these questions at the point of when recruiting children. (Sonia Livingstone, UK)