Have you ever heard of Fitt's Law?
"Fitts’s Law allows to predict a time it takes a user to point at an object using a specific pointing device (such as a mouse, trackball, trackpad, or even a finger)".
At a website about Fitt's Law - http://fww.few.vu.nl/hci/interactive/fitts/, you can collect data on how long it takes a user to point at an object comparing devices - skip to step 20 in the tutorial to go directly to comparing pointing devices. For example, you want to collect data on whether a student is faster using a traditional mouse or a track pad. This website takes you through a series of exercises where you click on various points using different different pointing devices. Then a graph is generated comparing the time is takes to click using the two devices.
The picture above is the data collected when I tested Fitt's Law on myself using a track pad (blue dots) versus a traditional mouse (red dots). I could have easily predicted that I would be better with a traditional mouse. I am very clumsy with a track pad.
If you go through the entire Fitt's Law presentation at the website, it is very informative on determining the location, distance and size of buttons and other elements. It explains why certain locations are easier to click on and view.
Thought I would pass it along to those who are involved in assistive technology evaluations. Seems like it would be a great starting point to compare a student's abilities to use pointing devices.
Reference: Fitt's Law Demonstration. Retrieved from the web on 3/5/14 at http://fww.few.vu.nl/hci/interactive/fitts/.