## The Development of the ThinQu Keyboard Layout: Factors that Influence Typing Effort

The ThinQu Keyboard Layout is an optimized keyboard layout I recently developed for standard keyboards. It is designed to maximize both typing speed and comfort.

It turns out to be extremely costly and difficult to build a model for typing comfort or effort. In existing studies, a regression model with several variables is usually built to measure typing effort and compare a few different layouts. The regression coefficients are either calculated by real data or purely speculated. The structures of these models are flawed due to the inflexibility of regression models and lack of data to estimate the coefficients accurately. It’s very costly to obtain real human data in typing speed and effort for multiple layouts because of the low population size and high learning cost of newer layouts. In addition, it’s very hard to measure typing effort and time is not a good proxy for effort; wasting time in waiting for other fingers to finish is more relaxing than spending time to get to the target key.

There are a couple of variables known to correlate with typing effort and I will go through the complexity of each one although it’s hard to talk quantitatively without empirical data. All frequency data come from the Norvig study.

### Key location and effort

Workman‘s layout nicely gives each key an effort score. The main inaccuracy is that the N key (of QWERTY keyboard) should be rated a 2 according to the symmetry with the V key. Secondly, the effort score for the low ring finger keys should be more like a 3.5 instead of a 4. Note that due to the difference in the right hand base keys, there is an extra middle column in ThinQu which would be rated a 5 or 6.

From the diagram, we can see a strong interaction between row and finger. Missing this interaction is the major drawback in carpalx’s model and implicitly in Colemak and many other layouts.

To place the most frequent letters in the best locations to reduce finger movement, we consult the letter frequency chart, which is adjusted for the multi-letter keys th, in, qu, and tion:

Note that h loses more than half of its usage due to the th key. The in key takes away 28% of the load on i and n, alleviating the pinkies. Continue reading “The Development of the ThinQu Keyboard Layout: Factors that Influence Typing Effort”

## Introducing ThinQu, the Fully Optimized Keyboard Layout

There has been many attempts to improve the QWERTY keyboard layout. Dvorak maximizes hand alternation; Colemak and many others emphasize on easiness to switch from QWERTY; Workman improves on these by considering the effort of lateral movements and the interaction between finger and row; Q*MLW* layouts provide the optimal solution of a quantitative effort model but fails to consider the factors raised in Workman. I generally agree with Workman’s finger strain mapping.

To design the most ergonomic keyboard layout, all of the advantages of the existing layouts are considered. The ThinQu layout has the following features in common with its predecessors:

•  As much as 60.6% of letter typing is done with the eight base keys (lower than Colemak’s 65.0%, because of the two-letter keys). 80.1% of the letter typing is in the 14 keys rated 1-2 by Workman. There is a strong correlation between letter frequency and Workman’ rating.
• Hand alternation is strongly favored. Within each hand, hand rolling (consecutive letters on the same row using adjacent finger) is favored.
• Same-finger movement is strongly penalized, which provides motivation for a more even frequency distribution across fingers.
• Lateral movement of the index and little finger is strongly penalized. The usage of the middle columns excluding numbers is 8.9%, compared to Workman’s 7.0% and Dvorak’s 14.8%.
• Hand utilization is more balanced with only a slight consideration for right-handedness. 49.7% of letter typing is done by the right hand. If including punctuation marks and Shift but not numbers and special keys like Enter, 51.4% of the typing is done by the right hand.
• With a priority for optimizing typing effort and speed, easiness for a QWERTY user to learn is minimally considered. No letters, four punctuation marks, and all numbers are in the same place as QWERTY. Three letters stay on the same finger as QWERTY. Users wishing to put less effort in learning the ThinQu layout should consider using the transitional ThinQu layout.

• The most frequent and the third most frequent bigrams, th and in, have their own keys. The in key also lessens the burden of the pinkies by pressing i and n keys less. A third two-letter key, qu, replaces the q key since u follows q 99.1% of the time. Thus the name ThinQu. Also, Shift+in does not produce In, but rather the most common 4-gram – tion. Note that the bigram keys still output lower-case letters when CapsLock is on.
• The base keys are shifted to the right by one space so that the right pinky is closer to Enter, Shift, and Backspace. It also redistributes most of its duties in punctuation marks to the new middle column for the index fingers. Now the right index finger rests on the K key of QWERTY. I recommend that you physically swap the J and K keys so your index finger can still feel the bump.  For those using a split keyboard, the non-shift version of ThinQu is recommended.
• All modifier keys in Windows and third party applications are still in the QWERTY layout. You can keep using Ctrl+C and Ctrl+V keys in their usual location.
• Utilization frequency for each finger is related to that finger’s strength but with finger movement in mind – less moved fingers can bear a higher frequency.
• The locations of punctuation marks are optimized by considering their frequencies. Square and curly brackets are available through Alt Gr.
• In addition to brackets,  letters with diacritics and other less often used symbols can be entered by pressing Alt Gr (right Alt or Alt+Ctrl). The layout is identical to the English international keyboard in Windows. Square and curly brackets along with an added  (en dash) symbol are placed in the home row.

• There is a programming version that makes symbols more accessible by some rearrangement.
• Users can modify the layout to their preference by editing the .klc file. Programmers can rearrange the symbols in the programming version to suit their programming language. This article lists the frequency distribution of symbols for each programming language.

The ThinQu layout makes the following assumptions:

• The ThinQu layout is only suitable for touch typists.
• It was designed for keys laid out in a QWERTY style (i.e. columns are staggered) although the relative loss for an ortholinear keyboard to adopt ThinQu is very small.
• The language used is always English with punctuation marks, occasional internet slangs and abbreviated spelling, and limited account/password/captcha entering.