Today we published a flowchart on our sister website, Tax-Charts.com, regarding Treas. Reg. §1.937-1, which deals with when an individual is considered a bona fide resident of a U.S. possession. We now have 15 free flowcharts at Tax-Charts.com.
Generally, for an individual to be considered a bona fide resident of a U.S. possession, the individual must (i) be physically present in the possession for at least 183 days during the year (ii) not have a tax home outside the possession for any part of the year, and (iii) not have a closer connection to the U.S. or a foreign country for any part of the year.