Is the American Recovery and Reinvestment Act of 2009 working? At the time of the act's passage last February, this question was hotly debated. Administration economists cited Keynesian models that predicted that the $787 billion stimulus package would increase GDP by enough to create 3.6 million jobs. Our own research showed that more modern macroeconomic models predicted only one-sixth of that GDP impact. Estimates by economist Robert Barro of Harvard predicted the impact would not be significantly different from zero.

Now, six months after the act's passage, we no longer have to rely solely on the predictions of models. We can look and see what actually happened.

Consider first the part of the package that consists of government transfers and rebates. These include one-time payments of $250 to eligible individuals receiving Social Security, Supplemental Security Income, veterans benefits or railroad retirement benefits--and temporary reductions in income-tax withholding for a refundable tax credit of up to $400 for individuals and $800 for families with incomes below certain thresholds. These payments, which began in March of this year, were intended to increase consumption that would help jump-start the economy. Now that a good fraction of these actions have taken place, we can assess their impact.

The nearby chart reviews income and consumption through July, the latest month this data is available for the U.S. economy as a whole.

Consider first the part of the chart pertaining to the spring of this year and observe that disposable personal income (DPI)--the total amount of income people have left to spend after they pay taxes and receive transfers from the government--jumped. The increase is due to the transfer and rebate payments in the 2009 stimulus package. However, as the chart also shows, there was no noticeable impact on personal consumption expenditures. Because the boost to income is temporary, at best only a very small fraction was consumed.