I'd often heard that there was a variety of studies that showed that couples that lived together before marriage (in the US, that is) had higher divorce rates than those who waited until marriage to shack up. Cohabitation before marriage has long happened at a higher rate in Europe than in here, and there didn't seem to be as much negative correlation there as is found here.
A post I saw yesterday (I think at Marginal Revolution) points to a new study that says that while there was ample statistical evidence backing premarital cohabitation being a bad thing, its effect has lessened with time. In fact, it says that in the most recent data available, there no longer seems to be a negative affect to shacking up early!
Maker Update: Self-Centering Drill Bits
1 hour ago