The arbitrary rule followed was to assign split census tracts to the PUMA with the largest land area overlap. This ensured that a census tract was always uniquely assigned within PUMA type. Usually these are fairly large holes which are census tracts that are only water areas which did not get a PUMA code assigned. In all cases, the census tracts constituting these holes were queried and the islands deleted. Certain holes did not have census tract boundaries underneath.
Holes are a fairly infrequent occurence and resolved using the approach mentioned above.
Noteworthy in these cases is that tracts along water areas are often coded differently. Overall though, the coast and shore lines are pretty well defined. This means that the target PUMA boundary does not exactly match the surrounding PUMAs, if viewed at high resolution scales. Rather than lose information, it was decide to create these polygons this way. As an example, view the large PUMA in the city of Denver, Colorado.