ADP is a private company that handles a lot of corporate payrolls, but by no means all, so they miss some regions and some types and sizes of businesses. The government number is the better (more accurate) number generally, but people watch the ADP to try to get a preview of it. Sometimes that doesn’t work well.
I don't know that one is more accurate than the other - both just take samples of data and extrapolate from there. The ADP number is based on actual payroll activities for their customers. The BLS is based on phone survey results, but I don't know how large a sample. I'm 60 and have never been called, so I imagine it's not a big number each month. The BLS number also is subject to "seasonal adjustments", which attempt to smooth out the numbers through time to take into account variations that occur normally, such as summer vacation hiring slowdowns, Christmas hiring (and hiring slowdowns), etc.
I would never take one single report as gospel,but rather the trend-lines developed over multiple periods.
Right on. Thank you for the explanation. So the ADP info is just another data point but the BLS numbers should be considered the authoritative superset?