The association of visual impairment with demographic variables such as age, gender, education and occupation were assessed using multiple logistic regression analysis.
In the O*NET data collection program, samples of workers in each occupation were assessed using questionnaires including items on work and worker characteristics.
Socio-economic class (SEC) was assessed using the occupation of the chief earner in the household and was coded: AB, managerial/professional; C1, supervisory; C2, skilled manual; D, semi-skilled/unskilled manual and E, state pensioners or casual/lowest grade workers.
The effect of parental occupation and family affluence on episodes of drunkenness was assessed using separate logistic regression models controlling for age.
Physical activity was assessed using a previously validated 4-level occupation and recreation activity index [ 10].
Socio-economic status was assessed using surrogate markers such as the occupation of the primary caregiver, numbers of rooms at home, car, television, cell phone and internet connection.
Socio Economic Status (SES) in 2002 was assessed using a full description of the occupation of the twins according to the descriptions provided by the Central Office for Statistics in the Netherlands.
Socioeconomic status was assessed using a wealth index based upon current occupation, household income, assets and household facilities [ 27].
Socio-economic status was assessed using the Kuppuswamy score, a questionnaire method, based on education, occupation and income [8].
Socio-economic status (SES) was assessed using Kuppuswamy score, a standard questionnaire method based on education, occupation and income of the main breadwinner [ 31].
