stevep99 -- Thank you for the constructive feedback based on your initial impressions. I agree that the quest for an optimal layout is a subjective one, given that people have different needs and preferences, particularly with respect to different forms of fatigue, strain, and injury. I will be sure to state this more explicitly in the article.
Regarding the use of the little finger, my goal was to maximize the number of inward rolls for high-frequency bigrams while simultaneously reducing the number of same-finger, high-frequency bigrams. Using all four fingers on the home row helps to maximize the number of inward rolls for high-frequency bigrams and minimize the number of same-finger bigrams by spreading out the effort across the fingers. But of course this necessarily results in greater use of the little finger. I have in my software an optional matrix that weights the fingers according to their relative strengths. When I have made use of it, I ended up with more same-finger bigrams (as expected), but perhaps more people would prefer this if it means reducing use of the little fingers. What do you think?
The finger strengths that I am referring to are based on peak keyboard reaction forces (in newtons) from Table 4 of
"Keyboard Reaction Force and Finger Flexor Electromyograms during Computer Keyboard Work"
BJ Martin, TJ Armstrong, JA Foulke, S Natarajan, Human Factors,1996,38(4),654-664:
Do these seem like reasonable strength values to use, or do you know of more relevant published measures? Or perhaps a better gauge of predicting fatigue/strain would be relative speed? Dvorak measured taps per second over 15-s intervals, and I also evaluate using a separate publication of inter-key speeds. Again, what are your thoughts?
As for incorporating angle modifications for standard-staggered design, I primarily use ortholinear (Kinesis and Ergodox) keyboards myself, and am a bit wary of including penalties for this, as keyboards vary. But let me reconsider this for my analysis. If you have any suggestions for best practices, I would love to hear!
And thank you for the correction -- I have already made the change of date from 2017 to 2014 for the next round of review of the manuscript.
I appreciate hearing from you, as it makes this endeavor more enjoyable and will benefit the final outcome and manuscript.