Deterenc* (a typo for deterrenc*) occurs over 100 times in Worldcat, making it an error of moderate probability. I’ve wondered before how many typos are actually due to the layout of our common QWERTY computer keyboard. QWERTY was originally designed in the late 1870s as a deterrent to jams – other keyboard setups would jam if two popular letter keys near each other were hit in fast succession. C.L. Sholes, the inventor of QWERTY, made sure that common letters used together (think TH or ER) were set up on two different type-bars, so that when pressed together, they wouldn’t jam as easily. At the time, this increased the speed of typing. Now that type-bars aren’t an issue, some curse QWERTY’s popularity, a deterrent to the rise of other preferred keyboard layouts such as Dvorak. Typing deterrence on a Dvorak would confuse me – the letters are so far apart in comparison to the D, E, T, R, and C all clustered on the left on a QWERTY (only the N is alone in the distance below) but fortunately for me, it doesn’t seem as though QWERTY is going anywhere anytime soon.
(Example of a Dvorak keyboard layout courtesy of Wikimedia Commons)