... education, employment status and the number of persons living in the house-hold. About 20% of the individuals had missing values in any of the summands. Missing data were imputed bymeans of conditional ... mean of the general population norm, indicat-ing markedly impaired physical health status, the meanMCS score was similar to the general population norm,indicating that mental heal th status ... which is offset by an increase in reliability o n the other [19].Household income was calculated as the sum of the respondent’ s own earned income, earned income of other persons living in the household,...