Professor Scott Shane of CWRU's Weatherhead School of Management cites evidence that entrepreneurial activity is declining in the United States. The number of employer firms created annually has declined significantly since 1990, and the numbers of businesses created and those claiming to be self-employed have declined as well.

Most Americans would like to believe that this country is getting more entrepreneurial over time. While I wish this were true, the data don't agree. Policy makers need to take a look at these data and acknowledge the pattern. More important, they need to understand why the rate of entrepreneurship is declining over time.

What accounts for this trend? Shane thinks one reason is "the Wal-Mart effect."

Large, efficient companies are able to out-compete small start-ups, replacing the independent businesses in many markets. Multiply across the entire economy the effect of a Wal-Mart replacing the independent restaurant, grocery store, clothing store, florist, etc., in a town, and you can see how we end up with a downward trend in entrepreneurship over time.

That may be true. It seems to me that another likely contributor is the increased regulatory burden. It is well documented that regulation can increase industry concentration. Smaller firms typically bear significantly greater regulatory costs per employee than larger firms (see, e.g., this study), and regulatory costs can also increase start-up costs and serve as a barrier to entry. While the rate at which new regulations were adopted slowed somewhat in recent years at the federal level (see here), so long as the cumulative regulatory burden increases, I would expect it to depress small business creation and growth.