Let me start this post by saying I do not advocate defaulting or retiring from matches unless there is a valid reason. And in the case of defaults, they should be communicated ahead of time so as to avoid inconveniencing players that have to arrange to make a match and potentially drive significant distance and don't want to show up to find out they have no match.
That said, there are implications on one's NTRP rating from retirements and defaults that is is good to be aware of. So here goes.
I think everyone knows, and common sense dictates, that if a match is a complete default, it doesn't do anything for your rating one way or the other. In fact, most defaults only have the "winning" team entered so there isn't even an opponent to calculate a rating against. The defaults are entered as 6-0, 6-0 scores for sets and games won/lost purposes in team standings and for tie-breakers, but the score doesn't matter to the players' ratings.
But what about scenarios where a team or player show up late and tardiness penalties kick in? In this case, the match is not defaulted but games/sets may be forfeited if a team is late but not so late to make the entire match a default. This has the potential for impacting ratings in perhaps an unfair way as, to my knowledge, these scores are entered normally and there is nothing in the system to indicate how many games were actually played vs how many were from a tardiness penalty.
Thus, by being late and starting a match down 1-0, you have possibly hurt your rating as you've given up a game you might not have otherwise. Worse, and I recently had a report customer where this happened, you might have to forfeit a set 6-0 and start the match at that point. That will significantly affect a player's rating regardless of whether they win or lose. Certainly one doesn't want to default the match if it could be won, and as I noted above it isn't really fair to all players involved to not get to play, especially if all the players are there, but if the match is likely a loss anyway and you don't mind the 6-0,6-0 result for the team standings, defaulting the match instead of playing it would likely be better for your NTRP rating.
As far as retirements go, my understanding is that there is a point in a match where enough of it is played and it becomes a match that is counted, but prior to that point if a retirement were to occur it wouldn't be counted. I haven't seen an authoritative source and have heard differing views on what this point is, but believe it is most likely one set or 10 games.
So again, I would not advocate retiring in a match unless there is a real reason to do so, but if you are injured and clearly won't be able to continue and win the match and the injury is causing you to play well below your normal capability, if you don't want to adversely impact your rating you are better to retire before the first set is complete than to complete it and then retire.
Now, one might argue that retirements shouldn't be counted at all as they might not properly reflect the capabilities of each player. But I think the idea is that a retirement occurs usually due to an injury that occurs during the match and if it is bad enough to be a retirement, it happens immediately. In this case, the games played to that point were fairly played and it makes sense to include them.
The first issue with tardiness seems like a pretty serious flaw in the system. Now, tardiness penalties are probably not that common, and when they occur it is probably just a game or two so it probably isn't a big deal. But the full set penalty certainly impacts ratings in an unfair way it would seem.
What do you think?