How Did the BLS Arrive at the Figure of 243,000K New Jobs Created in January?

Total non-farm employment in the U.S., before seasonal adjustments, fell by 2,689,000 jobs in January. However, because it's typical for the economy to lose a large number of jobs after the holidays, largely in retail trade, construction, and manufacturing, the BLS estimated that the "normal" seasonal decline in employment should have been 2,932,000 jobs in January. The difference between the two numbers, of course, was 243,000 jobs, which was reported as an increase in employment. The fact that the size of the seasonal adjustment was more than 12 times the number of reported jobs, and more than 30 times the "beat" in economists' expectations, should provoke at least some hesitation in taking the number at face value.

Notably, the January 2011 and 2012 seasonal adjustment factors ( seasonally adjusted payrolls divided by unadjusted payrolls) have been the two largest factors used by the BLS since the 1960's, at 1.0166 and 1.0165, respectively. This compares with a January seasonal factor of 1.0155 a decade ago, and a factor of 1.0152 as recently as 2009. Now, a range of 0.0014 in the seasonal factors for January may not seem like much, until you consider that non-seasonally adjusted payrolls are presently about 130 million jobs, so variation in the seasonal adjustment factor alone amounts to a difference of 182,000 reported jobs. I'm not suggesting there's anything nefarious going on here, it's just that part of what we're seeing here is most likely a statistical artifact of the adjustment process.