John Haltiwanger, an economist at the University of Maryland, says he's skeptical of the GEM report given that it claims such a dramatic boost in start-up activity.

WSJ: Rise in Start-Ups Draws Doubters

Many small-business owners already struggle with managing turnover and absenteeism, says John Haltiwanger, a professor of economics at the University of Maryland, who adds that small firms generally don't have human-resources departments.

WSJ: Debate Over Sick Leave Intensifies

Davis and John Haltiwanger have found that oil price shocks account for 20% to 25% of the cyclical variability in employment growth--twice as much as for monetary shocks--and they documented who feels the shocks the most.

FORBES: A Shield Against The Next Oil Shock

But a study by John Haltiwanger of the University of Maryland, with two researchers at the US Census Bureau, finds that young firms, most of which happen to be small, account for much of America's jobs growth.

ECONOMIST: Small firms are a big problem for Europe��s periphery