The American Time Use Survey is the culmination of a design and development effort that lasted nearly ten years, including a pilot study in 1997 and full-scale field testing in 2002 (Horrigan and Herz, 2005). The ATUS uses a random sample drawn from households that have recently completed their participation in the Current Population Survey (CPS). Thus, for example, a household that had been included in the CPS in January through April 2002 (Month-in-Sample 1–4) and January through April 2003 (Month-in-Sample 5–8) was eligible for inclusion in the June, July or August 2003 ATUS.
 

Sample households are selected based on the characteristics of the CPS reference person, and the respondent is then randomly selected from the list of adult (age 15 or older) household members. All adults within a household have the same probability of being selected. During 2003, the ATUS collected over 1,700 diaries per month. Beginning in January 2004, the sample size was reduced to approximately 1,100 per month, a rate that is expected to continue indefinitely.
 

The American Time Use Survey is administered using computer-assisted telephone interviewing, rather than paper diaries as in many other countries. All ATUS respondents are assigned an initial diary day and are called on the following day. If the respondent is unavailable on that day, subsequent contact attempts are made on the same day of subsequent weeks. This procedure maintains the proportional assignment of respondents to days of the week.
 

The core time diary of the ATUS is very similar to other time-budget surveys. The respondent is asked to take the interviewer through his or her day from 4 AM through 4 AM of the following day (the interview day). The respondent describes each activity, which the interviewer either records verbatim or, for a limited set of commonly performed activities (such as sleeping or watching television), hits a precode button. The verbatim responses are coded to a three-tier scheme, going from top-level category of activity, to sub-categories, to descriptions of very specific actions that together are considered to comprise a single third-tier activity.
 

Only the respondent’s primary activity is recorded and coded; if the respondent mentions secondary activities performed simultaneously, these are recorded but are not included in the total time inputs and are not classified using the three-tier scheme. For each episode, the ATUS collects either the ending time or the duration of the activity. In addition, for each activity the survey asks where the respondent was and with whom, unless the activity is sleeping or grooming (neither location nor with whom is asked) or working at a job (only location is asked). The “who” codes for household members refer to specific individuals.