42 QUARTERLY JOURNAL OF ECONOMICS TABLE III THE RETURN TO VARIOUS USES OF COMPUTERS,OCTOBER 1989 (DEPENDENT VARIABLE:In (HOURLY WAGE)) Use of computer Coefficient at work Proportion (std.error) Uses computer at work for any taskb 0.398 0.145 (0.010) Specific Taske Word processing 0.165 0.017 (0.012) Bookkeeping 0.100 -0.058 (0.013) Computer-assisted design 0.039 0.026 (0.020) Electronic mail 0.063 0.149 (0.016) Inventory control 0.102 -0.056 (0.013) Programming 0.077 0.052 (0.031) Desktop publishing or newsletters 0.036 -0.047 (0.021) Spread sheets 0.094 0.079 (0.015) Sales 0.060 -0.002 (0.016) Computer games 0.019 -0.109 (0.026) R2 0.495 a The sample and other explanatory variables are the same as in column(6)of Table II. b.The computer use dummy variable equals one if the worker uses computers for any of the ten enumerated tasks or for any other task. c.The dummy variables for any specific computer task,and the dummy variable for any computer use,are not mutually exclusive. cant because it suggests that using a computer for nonproductive activities does not enhance earnings.If the positive premium associated with computer use documented in this paper were reflecting characteristics of employers,such as ability to pay,we would expect workers who use computers exclusively for playing games to also have a large positive premium;this clearly is not the case. III.IS THE COMPUTER WAGE DIFFERENTIAL REAL OR ILLUSORY? A critical concern in interpreting the OLS regressions reported above is that workers who use computers on the job may be ablerQUARTERLY JOURNAL OF ECONOMICS TABLE I11 THE RETURN TO VARIOUS USESOF COMPUTERS, OCTOBER198ga (DEPENDENT VARIABLE: In (HOURLY WAGE)) Use of computer at work Proportion Coefficient (std. error) Uses computer at work for any taskb Specific Taskc Word processing 0.398 0.145 (0.010) Bookkeeping Computer-assisted design Electronic mail Inventory control Programming Desktop publishing or newsletters Spread sheets Sales Computer games R2 a. The sample and other explanatory variables are the same as in column (6)of Table 11. h. The computer use dummy variable equals one if the worker uses computers for any of the ten enumerated tasks or for any other task. c. The dummy variables for any specific computer task, and the dummy variable for any computer use, are not mutually exclusive. cant because it suggests that using a computer for nonproductive activities does not enhance earnings. If the positive premium associated with computer use documented in this paper were reflecting characteristics of employers, such as ability to pay, we would expect workers who use computers exclusively for playing games to also have a large positive premium; this clearly is not the case. 111. IS THE COMPUTERWAGEDIFFERENTIALREALOR ILLUSORY? A critical concern in interpreting the OLS regressions reported above is that workers who use computers on the job may be abler