YEAR reports the survey year.

There are several other variables that report date information on the diary day.  See DATE for the date of the diary day, DAY for the day of the diary day, and MONTH for the month of the diary day.

The ATUS interview took place 2-5 months after the final CPS interview.  Date information is also available for the final CPS interview.  See MONTH_CPS8 for the month of the final CPS interview and YEAR_CPS8 for the year of the final CPS interview.

CASEID is an identifying number unique to each household. 

CASEID is the same as TUCASEID which is on the public use ATUS files. For user convenience CASEID has been converted to a numeric variable. Users who are trying to match ATUS-X files with public use ATUS files must be sure that CASEID and TUCASEID are of the same type.

SERIAL is an identifying number unique to each household.

Scrambled pseudo primary sampling unit (PSU) collapsed stratum

STRATA is the scrambled pseudo primary sampling unit (PSU) collapsed stratum variable designed for use with CLUSTER in Taylor series linear approximation for correction of complex sample design characteristics. See the CLUSTER variable description for more details. The combinations of levels of STRATA variables define the strata in the sample, that is, where strata are non-overlapping subgroups that were sampled independently. These variables are mainly used to group observations into PSU clusters when computing standard errors. 

Sampling weights will often produce correct point estimates (such as means and variances). Some researchers may use additional techniques for the purpose of analysis and variance estimation. ATUS has provided STRATA and CLUSTER variables for this purpose. 

In the Stata software, researchers may submit the svyset and svydes commands once to define these variables in a data set (including sampling weights such as WT06). Other software may require that STRATA and CLUSTER be identified for each individual analysis. 

Users should note that STRATA and CLUSTER are not available for ATUS respondents whose final CPS interview was in April 2014 or later; these cases are assigned a value of 9999. To generate correct standard errors from April 2014 forward, users should use replicate weights (RWT06).