Table 1 Proposed measures of social class theory within the National Child Development Study (NCDS) cohort^a

1. Social background and early life circumstances

• Father’s Social Class: I; II; III-non-manual; III-manual; IV; V/other. Measured according to the Registrar-General’s schema which is regarded as an indicator of the prestige and skill levels of each occupation, at birth-1958 (Perinatal Mortality Survey).

• Mother’s father (Grandparent’s) Social Class: I; II, III-non-manual; III-manual; IV; V/other. Measured at birth-1958 (Perinatal Mortality Survey).

• Parental education: Was (a) mother, (b) father at school after minimum school-leaving age? Did not stay-16 years; did stay-16 years; did stay-16 to 18 years; did stay-19 or more years. Measured at birth-Perinatal Mortality Survey (PSM 1958).

• Receipt of free school meals: Does any child in household/family get free school meals at any point during schooling? Yes/No. Derived from variables measured at childhood sweeps NCDS2 (1969) and NCDS3 (1974).

• Family Financial hardships: number of times household experienced serious family financial hardships during cohort member’s childhood: 0 = none; 1 = at least once; 2 = at least twice. Derived from variables measured at childhood sweeps: NCDS1 (1965), NCDS2 (1969) and NCDS3 (1974).

• Overcrowding (defined as households with over 1.5 persons per room (excluding bathroom and kitchen)): number of times cohort member experienced overcrowding in childhood: 0 = never; 1 = once; 2 = twice; 3 = at least 3 times. Derived from housing variables measured during childhood sweeps: NCDS1 (1965), NCDS2 (1969) and NCDS3 (1974).

• Amenities: access to household amenities; indoor toilet, bathroom, kitchen: 0 = shared or no sole use; 1 = sole use of 1; 2 = sole use of 2; 3 = sole use of 3. Measured at survey sweep NCDS3 (1974).

2. Habitus and distinction

• Cognitive Ability measure: Draw-A-Man test score at age 7, as an indication of child’s general mental & perceptual ability (continuous variable). Measured at survey sweep NCDS1 (1965).

• Teachers’ assessment of child’s ability (derived ratings in Maths & English combined): 1 = A-level & higher; 0 = other (below average CSE grades 2–4/ little ability O-level or CSE 1). Measured at survey sweep NCDS3 (1974).

• Teacher’s view: child’s poor speech rating: 1 = not at all; 2 = somewhat; 3 = certainly; 4 = don’t know. Measured at survey sweep NCDS3 (1974).

• Imagined occupation at age 25: 1 = higher managerial & professional; 2 = lower managerial & professional; 3 = intermediate occupations; 4 = small employers & own account workers; 5 = lower supervisory & technical; 6 = semi-routine occupations; 7 = routine; 8 = students, occupations not stated or inadequately described or not classified. Measured at survey sweep NCDS2 (1969).

• Aspirations/plans after secondary school: 1 = full time studies; 2 = job, nothing more; 3 = part study & job; 4 = don’t know. Measured at survey sweep NCDS3 (1974).

• Aspirations, where child wants to continue full-time study: 1 = university, polytechnic; 2 = college education; 3 = art college etc.; 4 = other college; 5 = somewhere else; 6 = don’t know. Measured at survey sweep NCDS3 (1974).

• Leisure time activities: derived as a combined total number of leisure activities in childhood (0; 1; 2; 3; 4; 5 or more). Measured at survey sweep NCDS3 (1974).

• TV watching: Watched TV in the last 4 weeks? 1 = 5 times a week+; 2 = 3–4 times a week; 3 = 1–2 times a week; 4 = 2–3 times last 4 weeks; 5 = Once in last 4 weeks; 5 = Not done in last 4 weeks. Measured at survey sweep NCDS3 (1974).

• Book readership: Read books in the past 4 weeks? 1 = 5 times a week+; 2 = 3–4 times a week; 3 = 1–2 times a week; 4 = 2–3 times last 4 weeks; 5 = Once in last 4 weeks; 6 = Not done in last 4 weeks. Measured at survey sweep NCDS3 (1974).

• Newspaper readership: 0 = none; 1 = Broadsheet (Telegraph, Financial Times, Guardian, Times); 2 = Tabloid (Daily papers- Express, Mail, Star, Evening, Mirror, Sun); 3 = other (regional etc.). Measured at survey sweep NCDS4 (1981).

• Trades union membership/activity: Yes/No. Measured at survey sweep NCDS4 (1981).

• Voting behaviour (party voted for in general elections): 0 = none; 1 = Conservative; 2 = Labour; 3 = Liberal; 4 = Other (Welsh National, Scottish National, National Front, Communist, Workers Revolutionary Party (WRP)). Measured at survey sweep NCDS4 (1981).

• Voting participation (current voting intentions): 0 = none/spoil; 1 = Conservative; 2 = Labour; 3 = Liberal; 4 = Social Democratic Party; 5 = other; 6 = Refused/Don’t Know. Measured at survey sweep NCDS4 (1981).

• Religion: attendance at religious meetings: 0 = no religion; 1 = weekly or more; 2 = monthly or more; 3 = less than monthly; 4 = rarely or never. Measured at survey sweep NCDS4 (1981).

3. Exploitation and domination

Note: most information on sources of own income including rental income, shares, investments (including amounts) etc. was captured at sweep NCDS4 (1981). Where available, we further cross-checked the reported information for consistency with data collected from other adulthood sweeps.

• Main finance used to buy home: 0 = none; 1 = Building Society; 2 = Mortgage/Loan; 3 = Other way (e.g. Sale property, Savings). Measured at survey sweep NCDS4 (1981).

• Type of financial source of home purchase: 0 = none; 1 = Building Society Mortgage; 2 = Bank Mortgage/Loan; 3 = Other Loan (Local Authority Mortgage/Loan, Insurance Company Mortgage/Loan, Financial Company Mortgage/Loan, Loan-parents/in-laws, Government Home Loan Scheme, Other private loan); 4 = Gift/Inheritance; 5 = Other-way (Savings, sale of previous property). Measured at survey sweep NCDS4 (1981).

• Mortgage as a percentage of house price: 1: < 50%; 2: 50–60%; 3: 60–70%; 4: 70–80%; 5: 80–90%; 6: 90–100%; 7: 100%. Measured at survey sweep NCDS4 (1981).

• Housing tenure: 1 = own-outright; 2 = own-buying with help of a mortgage/loan; 3 = pay part rent and part mortgage (shared/equity ownership); 4 = rent it; 5 = live rent-free, including in relative’s / friend’s property; 6 = other; 7 = squatting. Measured at sweep NCDS8 (2008). Note that since this variable was captured throughout adulthood sweeps, we further checked survey sweeps NCDS4 (1981) - NCDS7 (2004) for completeness and consistency.

• Dwelling size: number of rooms (apart from bathroom & kitchen): 0; 1; 2; 3; 4; 5; 6 or more. Measured at survey sweep NCDS5 (1991). In the case of cohort members moving house, we cross-checked this information for consistency from other adulthood sweeps.

• Value of inheritance or gift or loan: in pounds (£). Measured at survey sweep NCDS4 (1981).

• Investments, savings and debt: in pounds (£). Measured at survey sweep NCDS4 (1981).

• Capital accrued: derived from the difference between property purchase price and size of loan or gift and ranked: 1-least to 5-most capital accrued. Measured at survey sweep NCDS4 (1981).

4. Location within market relations

• Highest educational qualifications attained: 0 = none; 1 = NVQ1 level/low-grade GCSE/O-levels or equivalent; 2 = O-level A-C grade/NVQ3 level or equivalent; 3 = A-levels/NQV3 level or equivalent; 4 = Degree/NVQ4 level or equivalent; 5 = Higher degree/NVQ5 level or equivalent. Measured in survey sweep NCDS7 (2004).

• Education attainment: age when cohort member left education. Measured at survey sweep NCDS6 (2000).

• Type of Secondary School: 1 = Comprehensive; 2 = Grammar; 3 = Private (includes Independent, Direct grant, special schools); 4 = Secondary modern; 5 = Other (Unknown reason). Measured at survey sweep NCDS3 (1974).

• Receipt of benefits: number of times cohort member received means-tested (e.g. unemployment, supplementary, family income support, family credit) benefits in adulthood: 0 = none; 1; 2; 3; 4 or more times. Derived from variables measured during adulthood sweeps: NCDS4 (1981) - NCDS8 (2008).

• Income and partner’s income: Family net income per week (£). Measured at survey sweep NCDS5 (1991).

• Debt and savings (own and partner’s): in pounds (£). Measured at survey sweep NCDS5 (1991).

• Unemployment periods: cohort member’s number of episodes of unemployment in adulthood 0 = none; 1; 2; 3 or more. Derived from variables measured at adulthood sweeps with the record of type of benefits received identified: NCDS4 (1981) - NCDS8 (2008).

• Own social class: Cohort member’s own social class. Measured according to the Registrar-General’s schema at sweep NCDS6 (2000).

5. Power relations

No measures identified for this class theory.