Mary Burke's most recent ad, "July," lists the same 10 Midwestern states, but shows Wisconsin lagging in job growth at the bottom of the list. That assessment uses the BLS Quarterly Census of Employment and Wages, which provides a quarterly count of jobs. It's regarded by economists as the most accurate job measure available.

While Walker says in his ad that Burke is criticizing Wisconsin's comeback, Burke has said the governor is "cherry picking" numbers and contradicting his previous commitments.

Walker himself has referred to the quarterly numbers (QCEW) as "the gold standard of jobs measurement" for the last two years. He criticized the accuracy of the monthly measurement (CES) during his 2012 recall election, when the numbers showed a loss for Wisconsin.

"A sample of 3.5 percent of the employers in the state is not an accurate job count," Walker said in May 2012.