June 2014

Is the workweek really overestimated?


We examined Robinson et al.’s results closely and found that their main table of results contains extensive internal inconsistencies—evidence of programming or transcription errors.4 When we used the methods described in their article to attempt to replicate the table, the results were consistent with our earlier work and showed a negligible mean difference between CPS actual hours and diary hours. We also attempted to replicate Robinson et al.’s chart 1, which shows how the gap between estimated and diary hours varies with estimated hours. Our replication was qualitatively similar to theirs. However, the chart should be interpreted carefully, and the interpretation in Robinson et al. is somewhat misleading. We note instances of misinterpretation and discuss the proper interpretation.

ATUS data and the Robinson et al. analysis

The ATUS sample is a stratified random sample that is drawn from households that have completed their participation in the CPS and is weighted to be representative of the U.S. civilian noninstitutional population. The ATUS interviews occur 2–5 months after the final CPS interview, with most occurring 2–3 months later. Interviews are conducted every day of the year, except on major holidays; thus, the ATUS covers the entire year, except for the days before those holidays. In the time-diary portion of the interview, ATUS respondents are asked to sequentially report their activities on the previous day, along with information on activity start and stop times and location.

In addition to the time diaries, the ATUS updates most of the labor force information collected in the CPS. As mentioned earlier, the ATUS asks respondents to report their usual hours worked, and reports of usual hours worked and actual hours worked from the final CPS interview are available in the ATUS–CPS file.5 Thus, the ATUS files include reports of (1) usual hours worked on main and second jobs from the CPS and the ATUS and (2) actual hours worked on main and second jobs during the CPS reference week from the CPS. (See the following box for the exact sequence of questions in the CPS. The ATUS usual-hours questions are identical to those used in the CPS.)

CPS hours questions

Usual hours

HRUSL1< How many hours per week (do/does) (name/you) USUALLY work at (your/his/her) (job?/main job? By main job we mean) (the one at which (you/he/she) usually) ((work/works) the most hours.)

HRUSL2< How many hours per week (do/does) (you/he/she) USUALLY work at (your/his/her) other (job/jobs)?

Actual hours

HROFF1< Now I have some questions about the exact number of hours (name/you) worked (THE WEEK BEFORE LAST/LAST WEEK). (THE WEEK BEFORE LAST/LAST WEEK), did (you/he/she) lose or take off any hours from (work/(your/his/her) MAIN job), for ANY reason such as illness, slack work, vacation, or holiday?

HROFF2< How many hours did (name/you) take off?

HROT1< (THE WEEK BEFORE LAST/LAST WEEK), did (name/you) work any overtime or extra hours (at (your/his/her) MAIN job) that (you/he/she) (do/does) not usually work?

HROT2< How many ADDITIONAL hours did (you/he/she) work?

HRACT1< ((LAST WEEK/THE WEEK BEFORE LAST)/So, for (LAST WEEK/THE WEEK BEFORE LAST)), how many hours did (you/he/she) ACTUALLY work at (your/his/her) (job?/MAIN job?)

HRACT2< (THE WEEK BEFORE LAST/LAST WEEK), how many hours did (you/he/she) ACTUALLY work at (your/his/her) other (job?/jobs?)

Replication of table 1 from Robinson et al.

The main table from Robinson et al. is reproduced as the top panel of table 1. The authors used data from the 2003–2007 ATUS and restricted their sample to respondents who were ages 18 to 64. For all workers, they found that the difference between hours from the estimate questions and the time diaries ranged from 2.8 hours to 3.6 hours. (Robinson et al. used the rightmost six columns of table 1 to supplement their discussion of their chart 1, which we discuss below.) Note that the samples, and hence the diary hours, differ depending on what estimate question they pertain to, because the diary hours are “for the same groups of people that answered the respective estimate questions.”6

Table 1. Robinson et al. estimates of hours worked, 2003–2007 data, and internal consistency checks
Estimates of hours worked from Robinson et al.
Estimate questionHours ≥ 1Hours ≥ 20Hours ≥ 35



ATUS usual hours


CPS usual hours


CPS actual hours




ATUS usual hours


CPS usual hours


CPS actual hours




ATUS usual hours


CPS usual hours


CPS actual hours

Implied percentage of men in the sample
Estimate questionHours ≥ 1Hours ≥ 20Hours ≥ 35

ATUS usual hours


CPS usual hours


CPS actual hours


Source: Robinson et al., "The overestimated workweek revisited,” Monthly Labor Review, June 2011, and authors' calculations.

Table 1 also shows estimates for men and women. This information allows us to perform an internal consistency check on the columns of the table. Letting H denote average hours for the sample as a whole, H = pHm + (1 – p)Hw, where Hm denotes average hours for men, Hw denotes average hours for women, and p denotes the proportion of men in the sample. Neither sample sizes nor the proportions of men for each column are given in the table. However, it is straightforward to show that p = (HHw)/(HmHw), so the proportion of men in the sample can be derived from the table. The bottom panel of table 1 shows the implied proportion of men for each set of estimates.


4 So far, we have been unable to reproduce the results in Robinson et al.’s table 1. We have shared an earlier draft of this article with Professor Robinson and his coauthors. Robinson, who has written to us to state that he performed the data analysis for the ATUS–CPS comparison in Robinson et al., has been unable to locate the relevant programs as of this writing.

5 The ATUS does not collect actual hours worked during the previous week.   

6 Robinson et al., “The overestimated workweek revisited,” p. 48.

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About the Author

Harley Frazis

Harley Frazis is a research economist in the Office of Employment and Unemployment Statistics, U.S. Bureau of Labor Statistics.

Jay C. Stewart

Jay Stewart is a division chief in the Office of Productivity and Technology, U.S. Bureau of Labor Statistics.