Are people in a committed relationship happier than people who are
single?  By committed I mean dating the same person for a year or
more.

Hello kascott23-ga,

You define "committed relationship" as one that's lasted over a year.
I've seen couples who made a commitment almost instantly -- "love at
first sight" type of relationships. On the other hand, I've also seen
very long term relationships where neither of the parties felt a
commitment -- usually involving "commitment phobic" partner(s).

I don't think anyone will be able to answer your question unless you
clarify your terms. Interesting question!

Good luck.

~ czh ~