Element identifier
Stratum identifier
Cluster identifier
Gender
Age in years
Age under/over 45
Physical health hazards of work
Chronic morbidity
Psychic strain - 1st princomp
Psychic strain - dichotomy
Psychic strain - 3 classes
New cluster
New stratum
Sampling weight for analysis
Constant weight
Age in five categories
Psychic strain - inverted dichotomy