Many couples in the US move in together to save money.
But a new study by the Pew Research Center finds that may not be the best move for everyone.
Cohabiting has economic benefits for college graduates---but not necessarily for those with less education.
College graduates who live together have a higher median household income than those who are married.
They also have higher income than high school educated couples.
Children may be another reason for the difference.
College-educated couples living together were less likely to have kids.