“I use layout X and don’t have RSI”
vs
“I had RSI with layout Y then switched to layout Z and stopped having RSI”
I would be inclined to say that the latter is strong evidence that layout Z is better than layout Y for avoiding RSI, whereas the former is only weak evidence for layout X
Like I said—there is weak evidence for the former.
However—if you don’t have RSI, then it may not be because the layout is not optimal… it might be because you are less prone to RSI, or because you’re young and able to bounce back from RSI easily, or because you just haven’t been typing long enough to develop RSI yet.
Whereas somebody that already has RSI… already has it, so if you change layout and the RSI goes away—that’s pretty good evidence that the layout-change has had a direct effect on the RSI.
There is a big differences between:
“I use layout X and don’t have RSI” vs “I had RSI with layout Y then switched to layout Z and stopped having RSI”
I would be inclined to say that the latter is strong evidence that layout Z is better than layout Y for avoiding RSI, whereas the former is only weak evidence for layout X
Don’t think so. RSI is Repetitive Strain Injury, so any change in the pattern of use will make it better.
Like I said—there is weak evidence for the former.
However—if you don’t have RSI, then it may not be because the layout is not optimal… it might be because you are less prone to RSI, or because you’re young and able to bounce back from RSI easily, or because you just haven’t been typing long enough to develop RSI yet.
Whereas somebody that already has RSI… already has it, so if you change layout and the RSI goes away—that’s pretty good evidence that the layout-change has had a direct effect on the RSI.
Correct. What it’s NOT good evidence for is the claim that the new layout is better. It’s sufficient for it to be only different.