44 QUARTERLY JOURNAL OF ECONOMICS TABLE IV THE RETURN TO COMPUTER USE AT WORK,HOME,AND WORK AND HOME (STANDARD ERRORS ARE SHOWN IN PARENTHESES. Percent of Type of October 1984 October 1989 sample,1989 computer use (1) (2) (3) Uses computer at work 0.165 0.177 39.8 (0.009) (0.009) Uses computer at home 0.056 0.070 12.5 (0.021) (0.019) Uses computer at home and work 0.006 0.017 8.6 (0.029) (0.023) Sample size 13,335 13,379 Notes.The table reports coefficients for three dummy variables estimated from log hourly wage regresaions. The other explanatory variables in the regressions are education,experience and its square,two race dummies, three region dummies,dummy variables indicating part-time status,residence in an SMSA,veteran status, gender,marital status,union membership,and an interaction between marital status and gender.Covariates are the same as in columns (2)and (5)of Table II. who did not use a computer at all.7 On the other hand,individuals who used a computer at home and at work earned about 9 percent more than individuals who used a computer at work only.Results are similar for 1984. Some workers may use computers at home infrequently (e.g., because the home computer is mainly used by a spouse),so home computer use may not reflect"serious"computer use.To examine this issue further,the models in Table IV were reestimated for subsamples of women and men who were unmarried.For these samples,however,the results are strikingly similar to those in Table IV,again suggesting that computer use at work influences earnings and not characteristics that are associated with computer use generally.8 B.Estimates for Narrow Occupations As a second approach,I limit the CPS sample to homogeneous groups of workers.The largest narrowly defined occupational group in the CPS is secretaries.In 1984 some 46 percent of secretaries used computers at work;by 1989 this figure rose to 77 percent.Not surprisingly,three-quarters of the secretaries who report using computers on their job use computers for word 7.The effect of home computer use on pay may be biased upwards because some individuals may use computers at home for work-related tasks. 8.For unmarried men,a1 =0.186,a2 =0.013,and as =0.064.For unmarried women,a1 0.192,a2 =0.010,and a3 0.067.In both samples,only a is statistically significant at the 5 percent level.QUARTERLY JOURNAL OF ECONOMICS TABLE IV THE RETURN TO COMPUTER USEAT WORK, HOME, AND WORKAND HOME (STANDARDERRORS ARE SHOWN IN PARENTHESES.) Percent of Type of October 1984 October 1989 sample, 1989 computer use (1) (2) (3) Uses computer at work 0.165 0.177 39.8 (0.009) (0.009) Uses computer at home 0.056 0.070 12.5 (0.021) (0.019) Uses computer at home and work 0.006 0.017 8.6 (0.029) (0.023) Sample size 13,335 13,379 Notes. The table reports coefficients for three dummy variables estimated from log hourly wage regressions. The other emlanatorv variables in the remessions are education. exoerience and its sauare. two race dummies. three region'dummiis, dummy varrables-indicating part-trme statis, residence m an SMSA, veteran status, gender, marital status, union membersbrp, and an interaction between marital status and gender. Covariates are the same as in columns (2)and (5)of Table 11. who did not use a computer at al1.I On the other hand, individuals who used a computer at home and at work earned about 9 percent more than individuals who used a computer at work only. Results are similar for 1984. Some workers may use computers at home infrequently (e.g., because the home computer is mainly used by a spouse), so home computer use may not reflect "serious" computer use. To examine this issue further, the models in Table IV were reestimated for subsamples of women and men who were unmarried. For these samples, however, the results are strikingly similar to those in Table IV, again suggesting that computer use at work influences earnings and not characteristics that are associated with computer use generall~.~ B. Estimates for Narrow Occupations As a second approach, I limit the CPS sample to homogeneous groups of workers. The largest narrowly defined occupational group in the CPS is secretaries. In 1984 some 46 percent of secretaries used computers at work; by 1989 this figure rose to 77 percent. Not surprisingly, three-quarters of the secretaries who report using computers on their job use computers for word 7. The effect of home computer use on pay may be biased upwards because some individuals may use computers at home for work-related tasks. 8. For unmarried men, a1 = 0.186, a2 = 0.013,and a3 = 0.064. For unmarried women, cil = 0.192, a2 = 0.010, and cia = 0.067. In both samples, only a1 is statistically significant at the 5 percent level