Welcome SunnyLee, hope you enjoy the forums and Colemak as much as me :)

Yes, you can be sure that every key's position is carefully thought out. There have been quite a lot of suggestions on improving Colemak by moving some keys around but the state you see is quite optimized, I assure you.

As for why the H is where it is – I'd give it mostly to two things: the fact that all the keys under your fingers (ARST NEIO) are more often used, and that on its current position it reduces the same finger ratio. The letters that are hit by the right index finger (JLHBNKM) are chosen so it's not very likely to follow one another, thus you wouldn't have to hit two consecutive keys with the same finger. There could be other reasons but these I'm sure were factor in the design choice.

As a Colemaker for a couple of years now I can assure you I don't have any problem with the lateral "stretches". Like any other layout, Colemak has its own "character" and it takes a little while to get used to coming from another.

I'm in building construction if it matters btw :P I wouldn't worry too much about Shai's background (I have no information either). Just look at the happy users.

Exactly why I wrote lateral "stretches" in quotes. Because it's not like I hold my hand on place and only stretch the fingers.

A a once-in-a-lifetime, forever-irreversible decision? No, I don't think so, unless you type a lot of texts everyday as part of your job and so you can't afford to invest time to learn a new layout.
I have tried Dvorak, Carpalx, Colemak, Workman, Norman and Vjustinak(no good atm) , in that order, and in the end I got back to Colemak and it felt like coming back home.
Dvorak was not bad, except for the shorcuts and all that L,S,... positions. I didn't like all the other layouts, I felt uncomfortable with all those other ones.

(I am currently trying to design a layout better than Colemak, but ,even if I succeed, Colemak is already a very good option in my opinion and other people's and I'd recommend it to anyone)

Some interesting information about Dvorak:
https://infohost.nmt.edu/~shipman/ergo/parkinson.html

I've looked, and I've found neither "professionals" nor "actual evidence". Apparently, there are no medical researchers interested in keyboard layouts, and consequently, there are no studies. So we don't really know anything. For instance, we don't know:

• How long it takes on average to retrain to Colemak,

• whether an individual would be expected to be faster on Colemak than on QWERTY, or

• whether or not Colemak is less likely than, say, QWERTY or Dvorak, to induce pain or RSI.

What we do have is statistical analysis of varying rigor --- Tony_VN sums it up neatly in his post above --- and of course the collective experiences of the members of this forum. There is plenty of anecdotal evidence that Colemak is great, but if your standard of evidence is controlled studies, then you're out of luck.

By the way, if you're typing QWERTY at 120 words per minute, why are you changing layouts?  Won't it be an enormous hassle for a minute benefit?

That's exactly what I'm going for: comfort. I learned to type when I was 8, as my family was a very computer-based, programmer-centric family. My father (now retired) had his run-in with RSI, and my mother now can't type for longer than an hour without finger pain, presumably from arthritis (she REFUSES to see a doctor).
As for me, I only recently started looking into this after my brother started to complain about finger pain while typing (more than usual), and he's only 32! Then again, I probably won't be typing as much as he would, considering he's in software engineering and I'm planning to go into a Psychology field, but either way I don't see many downsides, since I'm not terribly busy. Might as well start now while I'm 20 instead of after I start feeling pain. Comfort is key.

And yes, the lack of controlled studies is disappointing. With Colemak it's understandable, considering it's relatively new, but Dvorak, which has been around for quite some time, I still can't find any recent, extensive studies. However, with ergonomists studying the causes of RSI and motion economy which both seem to be incorporated into Colemak (less movement of fingers, avoiding awkward hand movements/positions as much as possible), I find this far more reliable than the anecdotal evidence from posts of people not liking it because they "tried it for a day" or liking it because they are more comfortable (while "typing at 1/4 of my original speed").

You're right though debois, I still need to take everything with a grain of salt. I do wish there was more research done on this, considering how common the keyboard is in the world today. Although the actual keyboard shape is more important than the layout I still think it does make a noticeable difference and I hope to not suffer any serious pain from typing.

...Nah, who am I kidding? The biggest factor is the status. "Hey, I know multiple layouts!" :P

Yeah... but many split keyboards are membrane crap so beware. I'd rather use a good mechanical keyboard with the Angle/Wide mods (see my sig topic) than a curved/split Microsoft or Logitech "Ergo" aka The Emperor's New Ergonomic Keyboard.

Agreed, especially on the "choice" part. It seems that each newer layout that comes out claims to "improve" the previous layout, with the appropriate statistics to back it up. Since I don't *plan* on changing layouts often throughout my life, I'd be better off picking the *best* layout that's available right now instead of waiting for the perfect layout while sticking to QWERTY. Too bad it's near impossible to define that, with every new iteration of a layout claiming new improvements, while supporters of the previous layout claim that the design is flawed, supported by their own claims.

I am also looking into different keyboards actually, two of them which I'm interested in: the Kinesis Advantage and the Typematrix. The Typematrix would make more sense for me, since it's more portable and I'm working on my laptop half the time in the library (and the Kinesis is far too expensive for me ATM). I'm using a Thinkpad X220, which already has a great keyboard, but I don't think it'll ever beat a keyboard specifically designed to be ergonomic.

I don't mind typing in QWERTY, but I've never come in contact with another keyboard layout until now to compare with. And comparing right now wouldn't be a fair assessment, considering how familiar I am with QWERTY, and how "comfortable" Colemak feels right now because I'm typing at a fraction of the speed. I won't know for sure until I am at least somewhat familiar with Colemak and type at a decent pace, but I don't know when that will be.

For now though, as you said, better habits would produce a much better outcome and is the least cost-effective to fix. I'm trying to take frequent breaks while typing, stretching, etc. Hopefully, combining all these factors (layout, ergonomic keyboard, better habits) will significantly decrease any chances of injuries in the future.

Must have missed that part.

It's hard to determine the effect of advantages and disadvantages. Some have longer fingers, some dislike the upper row, some think hand alteration is better and some prefer rolls.

It'd be nice with a compiled list of the more objective stats like distance, same-finger, finger balance etc. But that's available with the keyboard layout analyzers I think? Again, they tend to spew out more data than you can digest and it's up to your subjective preferences what to look at.

Holy poop, time sure does fly fast. I can't believe it's been 8 months already. Just thought I'd write some thoughts in case it may in some way be helpful.
Around February, I switched to Dvorak just to see if it's any better. Also, I just wanted to see if I could do it as a challenge. After I hit an average of ~80WPM (which I based off of Typeracer's last 10 races' speed), I started feeling some tingling in my right pinky finger when I would type for more than an hour. This was a bit of an issue, as most of my lectures are 75 minutes long and I have some profs that churn out massive amounts of information. (Though the problem is more likely a deficit in my notetaking skills, but either way, I would like to type more than an hour without this tingling feeling).

So I switched BACK to Colemak and have been typing it ever since. My "best speed" on Typeracer is 143WPM, and my average is ~100WPM (again, just on last 10 races). I think I need to look into some other websites though, as most of the quotes in Typeracer I now recognize.

The shortcuts, which have been said by a lot of people on this forum, really are nice to have. The only one I'm missing is D, which isn't too common compared to some other ones. It's much nicer to have T and R be closer (and P to some extent). I've noticed that I tend to do Ctrl + Backspace quite a lot, and I still have to get used to doing the Ctrl with the right hand and the backspace with the left. I wish I fixed this while I was learning, but now I'm very used to turning my wrist to hit both Ctrl and Backspace with my left hand, and that causes some pain after a while. I bought a Filco Minila, and that lacks a right Ctrl, so I'll have to find some workaround there.

But all in all, I'm loving Colemak. It's very comfortable for me now, and I just *feel* all the rolls flowing smoothly. Off the top of my head, I really like typing the word "around" - it has a roll on the left and a nice circular motion with the right hand, with a hand alternation between the two motions. I'm glad I took this up, and I feel I'll be using it for as long as keyboards are around.

Good to hear that your journey of alternative layouts has such nice ending. By using a mechanical keyboard, your chance of hand injury are almost non-existent.