Clearly, modelling form is vital in any football game, be it management, simulation or whatever. But FML presents an interesting challenge - players might be making 1 or 50 appearances a day, depending upon the activity of their manager, and those appearances could be spread over a bewildering array of different types and levels of competition.
Take a team that is ranked 100th out of the 1000 teams in a gameworld - one could easily imagine them being the bottom seeded team in one competition and the top seeded team in another. So, in this tumultuous environment, how do SI model the concept of form?
Well, the answer has been to store form on a per-competition basis. It is this competition-specific form that gets fed into the match engine, and this idea has sparked some controversy. I can't summarise it better than Owen from GW4 did:
If Man United had lost their last 3 games in the Champions League, but then won 10 games on the bounce in the Premiership, when they return to play Champions League, their morale would be high because of how they're peforming in the Premiership, not because of how they've been peforming in the Champions League (since the 3 matches they lost were before their 10 wins).But there is a second effect - morale. In this case of Owen's, Man United would go in to that 4th Champions League game on a high thanks to their 10 match unbeaten run - the high morale would cancel out their form.
At the end of the day, there are a lot more factors going into determining a result in FML than can be made sense of. Teams are very equal - people assume that a team that is 100th will be many times better than a team which is 500th, but in actual fact the difference in their squad's average (hidden) Current Ability stat is usually in single digits. The players play a huge role, as well as tactics, morale... form is just a part of the picture. Individual competition form may not be a perfect solution, but it's good enough for the job and not a huge factor.
I always wonder with perceived problems like this if there is actually a familiarity problem.
By that I mean that managers play their FA opposition very frequently, both because they share the same FA and because they are likely online often together, so are more likely to enter the same unofficial competitions. You get used to those teams, and over time gradually your tactics come to reflect what is more likely to succeed against those teams you play most often.
When you step outside of that, you come up against a batch of teams that you are set up less well for, since you don't routinely face them. Usually for me this has meant getting gubbed for the duration of a cup or league...