After three years of surveying Minnesota companies, WorkplaceDynamics, the Star Tribune's partner in the Top Workplaces project, reports the state has more companies that meet its national benchmark than any of the other 30 markets the firm surveys.

"Minnesota has lots of Top Workplaces,'' said Doug Claffey, CEO of WorkplaceDynamics. "It is our largest Top Workplaces program. We have almost doubled the size of the program in three years, which is unprecedented.'' This year, 331 Minnesota companies participated, up from 273 in 2011 and 169 in 2010, the project's first year.

Beyond the large field of participants, there is an unusually deep bench of Top Workplaces here. In addition to this year's Top 100 winners, another 60 state companies met the survey firm's national standards benchmark but did not score high enough to crack the Top 100. That's the largest number of standard-setting companies among all the markets WorkplaceDynamics surveys, including Boston, Chicago, Dallas, Houston and Atlanta.

Why does Minnesota have so many Top Workplaces?

Our large and diversified corporate community is one possible explanation. The state is home to many large privately held companies, including Cargill Inc., the world's biggest private company, which ranked No. 24 on this year's Top Workplaces large-company list; it also has a high concentration of Fortune 500 companies, with 19 firms in the magazine's 2012 list. They range from transportation company C.H. Robinson Worldwide Inc. (ranked No. 14 on this year's Top Workplaces list of large companies) to Thrivent Financial for Lutherans (No. 21), ag co-op CHS (No. 22) and U.S. Bancorp (No. 30).

Claffey said he doesn't know specifically why Minnesota has so many Top Workplaces (the question was not part of the research project), but he said that healthy companies, regardless of size, tend to perform well when employees give them high marks on what he calls the "we factors.'' Those include such questions as "where are we headed; how are we are going to get there, and are we making a difference.''

Many Minnesota companies, it seems, are making that difference.