From the Wall Street Journal (page A2 in the print version):
Retail sales racked up hefty gains in April after lackluster results in March. But economists say the rebound partly reflects a statistical distortion.
The Commerce Department said retail sales rose a seasonally adjusted 1.4% in April, compared with a gain of 0.4% in March. The March figure was revised up from an initial estimate of a 0.3% gain. Last month's rise was much larger than many economists anticipated and the biggest climb since September sales rose 1.8%.
In interpreting this number, this seems like a sage observation:
"The March figures were suppressed by harsh weather and difficulty seasonally adjusting for an early Easter, so in April there was a correction," said Joshua Shapiro, an economist at MFR Inc., a New York economic-advisory firm. "You need to look at them together and come to the conclusion that the reality is somewhere between the two results."
So seasonal adjustment raises its ugly head again. Or does it?
Because Easter fell in March this year instead of April as it usually does, the Commerce Department adjusted for the increased spending that month, which resulted in a weak number that led to fears of economic softness.
But some economists believe they "overdid" the downward adjustment to March and made a correction the next month. Others point out that this March/April pattern is identical to prior years when Easter fell in March. A Commerce Department spokesman said, "We've always adjusted for Easter" so the results are "nothing new."
UPDATE: The Skeptical Spectator covers the sales report, and a whole lot more.