# Could Fitts Law be used to measure difficulty in platform genre games?

I've been learning about Fitts' law and am wondering if it's applicable to measuring the difficulty of platform type games where the challenge is to hit the platforms?

If so, this could be used to ensure there is a well designed difficulty curve.

I'm also wondering if anybody has heard if Fitts law was used to measure difficulty in a game.

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Interesting idea to measure jump-by-jump difficulty; it'd have to be a very simple game or a very rough metric to work as expected though, a lot more tends to factor into games than distance and target size. Fitt's law also doesn't take into account gravity; higher platforms are much harder to reach, or may be impossible to reach, I think a modification would be needed. – Ben Brocka Sep 14 '12 at 20:56
Being a gamer myself, I would say IMHO that while it is a measurable factor of the game's difficulty, there are several others that highly affect it. Ben mentioned gravity, but motion controls, acceleration and deceleration, character velocity, control responsiveness and sensibility and probably others I'm forgetting make a huge difference. – Alpha Sep 19 '12 at 23:42

## 1 Answer

Probably, though my brief literature search didn't turn up any examples of people actually measuring game difficulty using Fitts' law. One thing to keep in mind is that motor movements are only a portion of what might make a game physically or cognitively demanding, even in platform games which are typically quite simple. Users have to make additional decisions, such as which platform to jump to or where to attend (do I look at the platform I'm jumping to, or do I look ahead to anticipate the next jump?)

I did find one interesting paper by Looser, Cockburn, & Savage (2005), who use Fitts' law to predict movement time in first-person shooters. The authors found that the time taken to pan (using a mouse) to acquire a target could be accounted for by Fitts' law. So if the time to acquire a target (e.g. before an enemy starts shooting at you) is critical, it certainly suggests that your methodology could be used to moderate difficulty level, say, by placing enemies farthest away from the current position.

Again, this is mostly speculation as I don't think there are any actual studies that address your specific question. But your intuition seems quite reasonable.

Looser, J., Cockburn, A., & Savage, J. (2005). On the validity of using First-Person Shooters for Fitts' law studies. Proceedings of. People and Computers XIX, 2, 33-36. PDF

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