Questions on hours of work comparable to those in the pooled datasets were asked in a supplement to the 1991 Current Population Survey. Mean hours of work per day (5 days a week) were 8.6 for men and 7.7 for women. Fifty-seven percent of the men in the sample stated that they worked eight hours a day (see Figure 1). The most common pattern was for work to begin at 8 am and end at 5 pm. A comparison of work start and end times and the reported length of the work day suggests that the majority of workers excluded lunch breaks from reported daily hours of work. The questions asked in the 1973 Current Population Survey were somewhat different and usual hours per day were estimated from usual hours per week divided by usual days per week. When similar information is used to estimate hours per day in the 1991 data, the average length of the usual working day falls slightly to 8.4 hours for men and 7.6 for women. The reported work day may include overtime if overtime was “usual” but because the proportion of low wage to high wage decile workers receiving overtime pay did not change between 1973 and 1991, changes in overtime coverage are unlikely to bias my results. Although time diary studies suggest that the length of the work day is overestimated both in 1991 and in 1973, but particularly in 1991, this will not bias my estimates of changes in relative hours of work.
Despite a slight increase in the coefficient of variation of daily hours worked from the 1890s to the present (see Table 1), for men the distribution between the 90th and 10th percentiles has become more compressed because the majority now work an eight hour day (see Figure 1). However, for women the distribution first narrowed between the 1890s and 1973 and then widened between 1973 and 1991, largely because the widening of the distribution for full-time workers outweighted the narrowing of the distribution for part-time workers.

Wages in the 1890s were reported according to how the worker was paid, by the hour, day, week, month, year, ton, or piece. Sometimes total yearly wages are given as well. For men I construct two wage variables. One is strictly for the set of workers paid by the hour and is the hourly wage as given by workers. The second wage variable, which is my only wage variable for women, is an hourly wage estimated from any available information. Thus for workers who were paid by the day the measure consists of the daily wage divided by usual hours worked per day. For workers who were paid by the week or the month I estimated an hourly wage assuming a six day week.