Many folks are dismissing the negative GDP number from the first quarter by arguing that the Commerce Department’s seasonal adjustment is faulty. According to some estimates a correct seasonal adjustment could add as much as 0.8 percentage points, which would be enough to bring the first quarter GDP into positive territory.

However seasonal adjustments must sum to one over the course of the year. In other words, if weather and other regular seasonal factors are more of a drag on first quarter growth than the Commerce Department acknowledges in its current seasonal adjustment, then the Commerce Department must be understating the extent to which weather and other seasonal factors provide a boost to growth in other quarters. The cost of saying that the first quarters (this and prior years) is better than the data show is that it means the data for other quarters are worse than the current methodology indicate. In other words, this will not qualitatively change our assessment of how fast the economy is growing, even if it may shift the timing between quarters.