Nancy MacIntyre co-founded Fingerprint Digital shortly after her 50th birthday, a departure from the common image of the young startup entrepreneur. Eight years later, her children’s app platform employs 32 people, has raised $25 million from investors and plans to become profitable this year.

Older entrepreneurs like MacIntyre aren’t anomalies, though. A new working paper from the National Bureau of Economic Research suggests middle-age and older founders of high-growth companies are more successful than their younger counterparts. I recently wrote about MacIntyre and the NBER research for Forbes.com.