The payroll employment number comes from the establishment survey, and is mainly based on Social Security tax filings where every employee for who those taxes have been withheld and also paid by employers is counted. This is a very reliable number.

The main reason it is subject to revision from month to month is because large businesses submit their payments weekly, and small businesses submit their payments less often. Generally, the revision numbers are reflections of new data coming from small and mid-size businesses.

The unemployment rate comes from the household survey. This is one of the best-run research surveys in the world, actually, and it is the survey used to calculate the unemployment rate. One of the problems withthe BLS releases is that they report the changes in payrolls and the unemployment rate together, leading most people to believe that they are derived from exactly the same data. They are not.

The reports from Challenger and ADP come ahead of the government's highly anticipated monthly jobs report, due Friday, though their figures aren't always reliable predictors of the government's numbers.

Many people overlook the ADP report because they rely upon the Governments Employment Situation report to give the lay of the land. However, historically we have found the ADP to be the more accurate one in terms of the trend.