A menu of same-finger bigrams
I've evaluated Hands Down with many different analyzers, and where possible with a huge variety of sample texts. It consistently ranks in the top 5 layouts by some metric or another: frequently #1, sometimes at 4 or 5, but usually in the top #2 or #3 (by layout family). But stats are not the whole story. For the reasons stated above in the design goals for this project, I think that Hands Down has some merit. Here are some detailed stats from the Colemak-DH(mods) analyzer, that is great for quickly discovering potential problems with same-finger bigrams.
Allergy Warning. The stats here were processed on digital equipment developed by others, and used to develop (or promote) other layouts. These numbers represent only a snapshot in time, based on a weighted list of bigrams from one convenient analyzer, the Colemak-DH Layout Analysis Tool, with default settings. It's a reasonable, fast, configurable tool. Actual stats, like hardcore across the board analytics, are huge, complicated affair, and suggest a variety of conclusions. Use a different test bed, or a different methodology, and you'll likely have very different numbers. I could have tweaked these stats to reflect my own bias regarding index finger fatigue, as mentioned above, to show Hands Down in an even more favorable light (I have, and it does). I am offering these because they are clear and concise, are reasonable approximations of other results, and they are not my own calculations. All of the stats are from others' freely available analyzers, and are all noted throughout. I figure that if Hands Down performs well by someone else's metric, then it might be objectively something of value to others.All Hands Down variations deliberately try to distribute finger burden roughly aiming to slightly favor the index and middle fingers while producing a functional balance between the critical same-finger bigrams (SFB), neighbor-finger bigrams, and individual finger usage frequency. A layout with the lowest SFBs may over burden some fingers, or cause awkward row jumps, or other undesirable traits in practice. Any single metric alone cannot represent the best layout design.
Balanced Hand and Finger Diet
finger 0 6.31% finger 9 8.08%
finger 1 11.56% finger 8 10.06%
finger 2 15.62% finger 7 20.65%
finger 3 16.73% finger 6 10.99%
total L 49.77% total R 50.23%
Although this near perfect balance is exceptional, I feel that anything under about 3~4% feels balanced in practice...Any more than that and I can definitely feel the imbalance after a typing session. Swapping E<->A results in 16.98% for finger 7, and 13.07% for finger 9. See below for Pink E, Roll E, and Thumb E variations that all reduce the burden on finger 7, albeit with somewhat lower overall statistical scores.
Same-Finger Lickin' Good Bigram Frequency
finger 0 0.009% finger 9 0.003%
finger 1 0.319% finger 8 0.021%
finger 2 0.193% finger 7 0.360%
finger 3 0.116% finger 6 0.179%
total 1.309%
Hands Down primary design goal was to reduce same-finger bigrams, especially on the pinkies. It has among the lowest same-finger bigram burden and total bigram penalties in this critical metric. This is the measure that you feel really quickly when typing, perhaps more than any other. I feel that anything over 0.3% on any one finger is noticeable, and annoying with anything over 1%, or anything at all on the pinkies. But a warning, too: some layouts with really good bigram stats suffer with awkward sequences that are so uncomfortable that a slightly higher bigram number may be worth it. Hands Down is no exception. There will be awkward sequences.
Fat Free Same-Finger Bigrams
finger 1 NC 0.295%
finger 7 E. 0.245%
finger 6 FU 0.095%
finger 2 HR 0.079%
finger 2 RL 0.075%
Hands Down has among the lowest frequency same-finger and neighbor-finger bigrams, yet does not over-burden the awkward ring and pinky fingers. The added burden is taken up primarily by the strong middle finger. Phonetic analysis helped to isolate bigrams and balance finger usage to avoid co-occurrent phonemes placed on the same finger columns where possible, (QSX, CRM, HNL, and all 6 letters on each index finger). U attracts the fewest bigrams of any vowel so it is exposed to the most letters, and OE is the least frequently occurring vowel bigram, though they are the first and fourth most frequently occurring letters.
Low Carb Neighbour-Finger Bigrams
finger 8–7 BE 0.644%
finger 1–2 CH 0.518%
finger 9-8 AI 0.483%
finger 7-8 E, 0.406%
finger 8-7 IO 0.328%
Exceptionally low frequency neighbour-finger bigrams, similar to the other top ranking layouts. Trigram analysis is much harder to measure, and very sensitive to physiological sensations, and linguistic (word/meaning) influences because we're getting closer to spelling/sounding words out. I couldn't find an analyzer to help. The theory is that if the bigram numbers are low, then the trigrams will require a shift away from a finger or two, and it'll sort itself out. This is true in practice, but some awkward sequences still occur. The C-vowel-M tri-gram sequence is the most annoying to me on Hands Down.
Avocados are good for you
Some of the better performing layouts encourage "good bigrams and trigrams" as a part of a healthy typing diet, rather than avoiding same-hand bigrams altogether. Depending on the pattern, I agree with this. On the consonant hand, the most common consonant bigrams are deliberately placed for comfortable same-hand rolls or rakes, such as TH, and the most common N-bigram group of NG, NT, ND, and WH, LD, and the GH+T bi-gram is very easy one-hand sweep "the blighted ghost is happy." On the vowel hand, the least common vowel bigram, OE, is on the powerful middle finger. So, while finger 7 is heavily used, it is almost never used in quick succession on a different key. The result is that all of the vowel bigrams are easy rolls. OU IO EA EI AE IE. Bonus: LS isn't bad, a common Dvorak complaint. The L-R hand inversion of Dvorak is intentional, as it leaves more keys on the hand they were on QWERTY, which has made the layout easier for me to learn, and may help when necessity arises that you must resort to QWERTY.
Check out this layout evaluator that compares many layouts using weighted bigram lists from multiple languages. It shows many interesting things, including the reality that there are many good layout options that perform statistically similar to each other, along the lines of what I've discussed and recommended here. It somewhat confirms a key design goal: Hands Down performs very well in English without penalizing use of other languages. Sure, other optimizations will be better in a given language or a given corpus, and different analyzers will argue one layout is marginally better than another based on the stats or weighting schema they use, but in practice I can only use one layout at a time...
A layout is also a matter of taste.
Artichokes to Ziti: I'm not trying to sell you on Hands Down, or make claims about the other layouts. I'm just excited that it works for me, and wanted to share it. You decide if it works for you, or doesn't. Sometimes significant variation occurs with different statistical weighting or sample corpus being analyzed. While a good number of layouts are close to Hands Down statistically, they all arrive at those similar-ish results in different ways, which means that typing on statistically similar layouts will likely feel very different—and that feel is very important. As much pun as I have had here with the name, there is, simply, no way to claim that any layout is, Hands Down, the beets, nor would that necessarily mean you should like borscht. Variations are GOOD FOR YOU—change it to suit your needs. Some keystroke patterns will freak someone out, and be no problem for someone else. That's why it's called the Hands Down Reference layout. I expect you to season it to suit your taste.
So always take stats with a dash of salt, knowing that what matters most in any Human Computer Interface is always the particular human. The important thing is that it works for the user, across a variety of texts they are likely to encounter (including languages). All this analytic stuff is just to help develop the layout, then communicate it to those who might want to use it—like a menu. It may look and sound delicious, but all that matters in the end is whether it is delicious to you.
