Case identification used to uniquely identify each respondent. In most surveys this is
constructed by concatenating the cluster or sample point number, the household number
and the respondent' s line number, but in some surveys this may be the questionnaire
number taken from the front page of the questionnaire.

V002 Household number is the number identifying the household in which the respondent was
interviewed, within the sample point. In some cases, this variable may be the
combination of dwelling number and household number within dwelling. In these cases,
the original variables are included as country-specific variables.