Rhythm
Rhythm refers to the flow and patterns of typing motion, particularly how typing moves between hands and fingers. Layouts Wiki categorizes every trigram into an action rhythm bucket, with an additional input-disrupted bucket for chorded events. The serialized stats expose the legacy 27-way single-action classifier plus input_disrupted; only a subset of those buckets is displayed on layout pages.
There are two main competing philosophies about the best rhythm for a keyboard layout:
Alternation: Dvorak was designed around alternation—typing that alternates between left and right hands with each keystroke. For example, the word data alternates hands on Dvorak:
Rolling: Colemak prefers rolls—same-hand sequences where multiple keys are pressed before switching hands. For example, the trigram oil is a smooth roll on Colemak:
There is no universal agreement on which is better. According to Ec0vid’s Keyboard Layouts Doc, 3rd Edition:
Which to favor between rolling and alternation is subjective. It can be said that alternation offers a more consistent typing experience, as it feels rhythmic and minimizes awkward sequences. Meanwhile, rolling has higher highs (words that feel very smooth) but lower lows (long same hand sequences). Regardless, it is not a matter of one or the other. Think of it more as a scale, with max alternation on one end and max rolling on the other. We have to decide where on that scale we want our layout to be.
Layouts Wiki displays several key rhythm metrics in layout analysis, focusing on patterns that significantly impact typing comfort and efficiency. These statistics are calculated both with and without thumbs to account for different keyboard types.
Explicit-event analysis semantics
Section titled “Explicit-event analysis semantics”Rhythm is classified from keymaxx’s resolved event stream. A single-action press, hold acquisition, or hold release participates normally; changing hold state does not interrupt rhythm by itself.
An event is chorded if an authored trigger acts on multiple physical keys or if the event coalesces multiple triggers. If any of a trigram’s three events is chorded, the trigram is counted once in input_disrupted instead of an ordinary rhythm bucket. Otherwise the existing single-action classifier applies.
Same-finger trigram categories include transient sustained keys but remove a hold sustained across the entire window. This records a physically relevant acquisition or release without mistaking a steady hold for repeated finger movement.
The “without thumbs” rhythm denominator excludes trigrams whose event-action sequence uses a thumb. A sustained thumb by itself does not remove the trigram from that denominator.
Same-row rolls
Section titled “Same-row rolls”Same-row rolls are measured over windows of two, three, and four events. Each event must act on one key, all on the same hand, with the fingers progressing in one direction without reversal or repetition. Radial rolls move toward the thumb; ulnar rolls move toward the pinky. These refinements retain the existing rhythm classifier’s treatment of transient same-finger patterns.
Across the entire window, the highest and lowest action-key Y coordinates may differ by at most two coordinate units, including the endpoints. For example, Y values zero and two qualify; zero and three do not. Press, Acquire, and Release participate equally, including their action-key coordinates. Sustained keys do not determine the row span.
Adjacent-finger same-row rolls additionally require each successive finger to be adjacent in the roll direction. They are included in the corresponding radial or ulnar total. Each current percentage divides by all event windows of that length.
Hand-run lengths
Section titled “Hand-run lengths”A hand run consists of consecutive events whose action keys use that hand exclusively. Press, Acquire, and Release each count as one event. A cross-hand chord ends both runs and belongs to neither. Sustained holds neither add to nor break runs: holding left Shift while typing with the right hand leaves the right-hand run intact, but releasing that Shift ends it.
Runs stop at decoded sequence boundaries and may be longer than five events. Each hand’s distribution reports the share of its runs at each length, preserving corpus frequency and the weights of equally optimal typing paths.
Finger gaps and holds
Section titled “Finger gaps and holds”Finger-gap and finger-hold distributions measure intervening events within each decoded sequence. A gap is the idle interval before, between, or after that finger’s uses. A held interval lasts while the finger has an active hold; unrelated actions contribute to its length. The acquisition and release endpoints are excluded from the intervening-event count.
Intervals cut off by the beginning or end of a sequence are included at their observed lengths. A finger never used in a sequence contributes one gap spanning that entire sequence. Zero-length gaps are included. Intervals never join across sequence boundaries.
Each finger’s gap distribution is normalized over its weighted gap occurrences, and its hold distribution over its weighted hold occurrences. An unused hold distribution is empty. These percentages describe interval occurrences, not the proportion of typing time spent holding or resting. Corpus frequency and alternative-path weights are preserved exactly.
A zero-gap percentage is conditional on that finger’s gaps, so it cannot be compared directly with SFB or SKB percentages over all bigram windows. Zero gaps also include sequence-edge fragments when the finger acts at the first or last event. The playground combines interval lengths of 10 or more into a single 10+ column; analysis retains the individual lengths.
Redirects
Section titled “Redirects”A redirect, also called roll reversal or pinball in some older literature, is a same-hand sequence that changes direction—either from out to in, or in to out. Some people believe that redirects are uncomfortable and error-prone, though others see them as fine.
For example, on QWERTY, the trigram fad is a redirect:
Layouts Wiki categorizes redirects by finger involvement to distinguish their relative difficulty. Currently, two types are shown for each layout:
Weak Redirects
Section titled “Weak Redirects”A weak redirect, also called bad redirect, is a redirect that does not involve the index finger or the thumbs. Most typists hold that because the middle, ring, and pinky fingers naturally move in concert with each other more so than the index and thumb, weak redirects are more difficult than other types of redirects. However, some typists have reported that muscle independence on the weak fingers can be built up with practice, making weak redirects comfortable for them.
On QWERTY, the trigram sad is a weak redirect:
The weak redirect stat is shown as a percentage of all trigrams.
Weak-ish Redirects
Section titled “Weak-ish Redirects”A weak-ish redirect (unique to Layouts Wiki) is a same-hand trigram that changes direction and involves at least one weak finger (ring or pinky) but also includes either the index finger or thumb. Some typists find this pattern difficult like weak redirects, but others have no trouble with it. While the index finger or thumb can provide some stability, the involvement of weaker fingers still creates coordination challenges.
On QWERTY, the trigram saf is a weak redirect:
The weak-ish redirect stat is shown as a percentage of all trigrams.
Other Same Finger
Section titled “Other Same Finger”Other Same Finger encompasses all trigrams that use at least one finger twice, excluding weak redirects to avoid double-counting. Some of these patterns include:
- Same-finger rolls (consecutive keys on the same finger)
- Same-key patterns (repeated key presses)
- Three-key same-finger trigrams
These patterns are problematic because they require the same finger to be used multiple times in quick succession. Ideally, a good layout maximizes the ratio of trigrams that use three different fingers.
Rolls to Alternations Ratio
Section titled “Rolls to Alternations Ratio”The Rolls : Alts ratio measures the balance between rolling motions and alternating motions in a layout. This ratio helps characterize whether a layout tends toward the rolling philosophy (higher ratios) or alternation philosophy (lower ratios).
A ratio of 1.0 indicates equal amounts of rolls and alternations, while higher values indicate more roll-heavy layouts and lower values indicate more alternation-heavy layouts.
Roll Direction
Section titled “Roll Direction”Roll direction refers to the movement pattern within same-hand sequences:
- Inward (Radial): Movement toward the index finger (center of keyboard)
- Outward (Ulnar): Movement toward the pinky finger (edges of keyboard)
Some typists consider inward rolls to be more comfortable. However, emphasizing inward rolls comes at the cost of other stats, so other typists prefer to optimize those other stats over favoring inward rolls.
2-Roll In : Out
Section titled “2-Roll In : Out”The 2-Roll In : Out ratio compares inward rolls (toward the index finger) to outward rolls (toward the pinky finger) for two-finger rolling sequences.
3-Roll In : Out
Section titled “3-Roll In : Out”The 3-Roll In : Out ratio compares inward to outward rolling motions for three-finger same-hand sequences.
Higher ratios indicate a preference for inward rolling motions, while lower ratios indicate more outward rolling patterns.
Thumb Rhythm
Section titled “Thumb Rhythm”Analyzing thumbs poses two major challenges.
First, on standard, non-split keyboards, the space bar can be pressed by either thumb, and each typist has their own individual preference about which thumb should press space. However, the thumb assigned to the space key has a significant effect on overall rhythm, so inasmuch as thumb rhythm affects typing comfort, a left thumb space typist will have a different experience from a right thumb space typist on the exact same layout. Layouts Wiki accounts for this by providing separate rhythm stats for both options.
Second, the thumb is significantly more independent than the other fingers, so some typists do not consider thumb rhythm as a factor in typing comfort. Layouts Wiki accounts for this by providing rhythm stats both with thumbs and without thumbs.