The article looks at how tax deductions for work-related expenses can affect efficiency. It finds that whether these expenses are necessary for increasing taxable income and if they are social costs play a big role. Commuting expenses should be taxed instead of getting deductions, as they might not really boost taxable income. Deductions for personal costs like housework and child care could be neutral, but if not, the right amount of deduction depends on how flexible people are in their work hours.