The Symmetric Typing Project

More comfortable typing technique. Better keyboard layouts.

Alternative Layouts - Performance Comparison.

The layouts presented in these pages (Niro and Soul), together with some other well-known alternative layouts have been analyzed using a simple scoring algorithm. The scoring is calculated based on the frequency¹ each key is typed, with keys valued at 5 (for the easiest keys) down to 0 for the most difficult. Only the best 20 keys have positive scores, but this should represent the vast majority of keystrokes. In addition to this position-based score, a penalty is applied for the frequency¹ with which consecutive same-finger key presses occur. Although relatively simple, arguably this scoring system encapsulates the main factors for assessing keyboard layouts. If you test them against other scoring systems, let us know the results!

The formula used for scoring is:

score = ( F5 ) + ( 4/5 * F4 ) + ( 3/5 * F3 ) + ( 2/5 * F2 ) + ( 1/5 * F1 ) - (same-finger)
...where Fs is the frequency of keys that score s.

This is also equivalent to:

score = [ (best 4) + (best 8) + (best 12) + (best 16) + (best 20) ] / 5 - (same-finger)
...where (best n) refers to the frequency of a keypress being one of the n best keys.

The scores for each key.

Using this scoring system we evaluated our layouts, plus some other well-known layouts including Colemak, Dvorak and Workman. As well as the overall scores we also show what percentage of key presses are covered by the best 4 keys (dark blue), best 8 (+light blue), best 12 (+green), best 16 (+yellow) and best 20 (+orange) keys.

Here are the results:

Layout Hand Balance
best 4
best 8
best 12
best 16
best 20
% same
Ease of
Soul 49:51 35.3% 62.5% 80.2% 86.8% 92.7% 1.4% ★★★ 70.6
Workman 51:49 34.0% 63.8% 79.4% 83.7% 93.6% 2.7% ★★ 68.2
Niro 55:45 36.6% 65.0% 75.3% 81.7% 89.1% 1.6% ★★★★ 67.9
Colemak 48:52 35.5% 65.0% 76.0% 82.5% 87.4% 1.4% ★★★ 67.9
Asset 53:47 36.6% 65.0% 73.8% 78.6% 86.0% 2.8% ★★★★ 65.2
Dvorak 43:57 29.6% 59.0% 65.0% 70.8% 79.1% 2.6% 58.1
Qwerty 59:41 6.9% 25.5% 51.5% 60.7% 78.3% 6.8% 37.8

According to this analysis, Soul is the best performing layout tested. Of the two layouts presented here, Soul scores a little better than Niro, but Niro is designed to be easier to learn. Nonetheless, despite the fewer keys moved, the Niro layout manages to acheive a rating on par with Colemak.

Of the layouts designed elsewhere, we find that Workman is marginally the best. But note it has a higher consecutive same finger ratio than either of the two layouts presented in this project, and with more keys changing relative to Qwerty, is also more difficult to learn. Colemak also performs respectably well, has the nice benefit of a low same-finger count, and is should be a little easier to learn than Workman, but is let down by not optimizing some difficult keys.

In summary, Soul is recommended as the overall best layout. Niro is nearly as good and should provide excellent performance for those seeking a less radical layout change from Qwerty.


¹ For our key frequency tests we use letter and bigram occurrences as published here by Peter Norvig. Only the alphabetic letters are included, the effect of punctuation and other symbols is not counted.