idcode
a numeric vector, NLS id
age
a numeric vector, age at current year
race
a numeric vector, race
married
a numeric vector
never_married
a numeric vector
grade
a numeric vector, current grade completed
collgrad
a numeric vector, college graduate
south
a numeric vector, lives in south
smsa
a numeric vector, lives in SMSA
c_city
a numeric vector, lives in central city
industry
a numeric vector
occupation
a numeric vector
union
a numeric vector, union worker
wage
a numeric vector, hourly wage
hours
a numeric vector, usual hours worked
ttl_exp
a numeric vector, total work experience
tenure
a numeric vector, job tenure(years)