What are the individual and household level files?

In some data files each row represents a unique household. These are household level files, e.g., a_hhresp a_hhsamp. In some data files, each row represents a unique individual. These are individual level files, e.g., a_indresp. Some data files are at multiple levels, e.g., each row in a_cohab represents each cohabitation reported by each individual. In each of these files, variables will be provided which will allow you to uniquely identify each row. For example, in a_hhresp it is a_hidp, in a_indresp it is pidp and in a_cohab it is the combination of pidp and a_cohabno. For a complete list of the levels and unique identifiers of each datafile see the List of datafiles and their descriptions section of the Main Study User Guide.