Amongst passes, those passes which are thrown into the end zone form a distinct subset, since they terminate possession for the offensive team, regardless of whether or not they are caught. Passes in the regular field of play which are caught, of course, just maintain possession for the offensive team, and can lead to further passes.
One of the things that makes ultimate frisbee unique is that an offensive player cannot accomplish anything by him/herself; they have to pass the disc to a teammate in order to advance the disc or score. What this means is that, offensively, there are two roles that must be filled on any given pass: there must be (1) a thrower and (2) a target. Analogously, a member of the defensive side also always plays one of two roles on a pass: (3) they can defend the thrower or (4) they can defend the target. Here, I have labeled a defensive player in role (3) as the "marker", and a defensive player in role (4) as the "defender".
I recognize that defense is not necessarily an every-man-for-himself endeavor, and that more than one defender may work together to defend either the thrower or the target. So long as the defensive team is playing man-to-man, however, the actors involved in the vast majority of passes boil down to just these four players. The minority of other cases can also generally be viewed in terms of this four-player paradigm without doing too much damage to the truth.
Along with a set of four actors, each pass has a result. The results that I have categorized here include: (1) a completion, (2) an incompletion, (3) a drop (by the target), (4) an interception (by the defender), and (5) a pass "defensed" (by the defender). It is also possible for a pass to be (6) blocked (by the marker), but that didn't occur in Monday night's game. One could also conceivably distinguish between incomplete passes that were thrown out of bounds and those that were not, but I did not do so.
Drops require a bit of a judgment call on the part of the scorer, which is unfortunately less than ideal. The basic rule of thumb (ha!) I went with was to count a drop whenever the disc hit the target's hands but was not caught.
The scoresheet is set up to record, for each pass, who the four actors were, what the result of the pass was, and whether or not the pass was thrown into the end zone. Everything else follows from those six fields of information. For those who are interested, other fields of information could be straightforwardly added to each pass for analytical purposes (distance and direction of throw, type of throw, direction of force, etc.), but I found that it is fairly time-consuming to do so.
With pulls, there are only two basic actors: the puller, and the player who catches/picks up/drops the pull. I have included this information in the box score and scoresheet, primarily for completeness' sake.