Mr. Rewrite always learns though editing. Today's lesson: The AP Stylebook calls for socio-economic (with the hyphen) rather than socioeconomic.
There's no stylebook entry on socio-economic, but a search of the electronic version yielded a reference in the hyphen (-) entry.
This differs from the Websters New World College Dictionary, Fourth Edition, which calls for socioeconomic. Mr. Rewrite wonders whether AP made a mistake in this entry. He'll tweet it to AP.