Keyboard manufacturers would have you believe that ergonomic keyboards increase worker productivity, reduce injuries, and increase typing speed, but the real benefits are murky. The body of research on ergonomic keyboards is inconclusive, with a number of studies showing that ergonomic keyboards are of dubious value or that they decrease productivity.
There are a few different ergonomic keyboard designs, the most popular are shown below from left to right: the split keyboard, the angled split keyboard (sometimes called a Klockenburg keyboard), and the contoured keyboard.
So which of these will make you the most productive? The most likely to prevent carpal tunnel and other injuries dreaded by programmers? Probably none of them.
There is research showing that ergonomic keyboards increase typing speed. There is research showing that the same keyboard decreases typing speed. Studies show that ergonomic keyboards increase productivity, that they decrease productivity, that they decrease injuries, and that they have no effect on the number or severity of injuries. Whatever conclusion you wish to show regarding ergonomic keyboards, you are bound to find at least a few studies supporting that conclusion.
Sifting through the research, the only clear trend that emerges is that much of the research showing the benefits of ergonomic keyboards was done by manufacturers of ergonomic keyboards, by companies who are in the business of injury prevention consultation, or companies that have some other vested interest in the success of ergonomic keyboards. Further muddying the waters, Google Scholar search results on the topic of ergonomic keyboards are polluted by marketing documents disguised as research, such as this document by Goldtouch, a popular brand of adjustable split angled keyboards.
So which keyboard should you buy? Scientifically speaking, it probably doesn’t make a damn bit of difference as long as you are comfortable and have had sufficient time to adapt to any peculiarities of your keyboard. Test a few out and then get a keyboard that you like. No matter if that is an ergonomic keyboard, a cheapo minimalist keyboard, an old school mechanical keyboard with backlighting, a medical grade waterproof keyboard, or whatever keyboard makes you happy.
There are plenty of other tweaks you can make to your work environment that do increase productivity (and are backed by solid scientific evidence). Read more about how to increase productivity by reordering your office, but forget about ergonomic keyboards.