A few weeks ago I read Thomas Friedman's new book, That Used to Be Us: How America Fell Behind in the World It Invented and How We Can Come Back. One of the early chapters begins with this quote from an unknown source:

It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change.

This is so true. I've been fortunate to work with incredibly smart people with incredible credentials: people who have worked at the top consulting firms and investment banks that have worked at some of the world's most admired companies -- Goldman Sachs, Apple, Google and Amazon -- and have attended the best colleges and business and engineering graduate programs. But when I think back on the people who were successful in the start-ups I've worked in, I've seen that there is almost no positive or negative correlation with those great credentials (great companies, great schools, high standardized test scores) and actual success in the workplace.

As the quote suggests, it really isn't the smartest or the strongest that are the most successful.

To emphasize this point, it's helpful to use a sports analogy here (I like sports analogies because sports is very results-driven and the results are extremely transparent).Regarding strength, you might think that the best NFL players are the strongest and most athletic and come from the best college football programs and had the best college football careers. But this isn't true at all. There are countless instances of great college football players not making it in the NFL -- particularly in the more complex and cerebral positions. Case in point: Tim Tebow won the Heisman trophy and a national championship at the University Florida, Tom Brady was a third string backup at Michigan.

Regarding intelligence, each year every professional football recruits takes the Wonderlic Test. It's a test that measures the intelligence of the player and is often used in making decisions about which players to draft. You might suspect that higher scores lead to greater success. Wrong again. Ryan Fitzpatrick, the Harvard educated, backup quarterback for the Tennessee Titans scored a 50 -- the highest score of any current player in the NFL. Peyton Manning, arguably the best quarterback in the NFL, scored a 28.

I see the exact same thing in the workplace. It isn't great credentials or talent or SAT scores that makes people successful in a start-up, it's traits like grit and humility -- and perhaps most of all, adaptability. Something to keep in mind when looking for "A-players" to join your team.