Rhythm
Rhythm refers to the flow and patterns of typing motion, particularly how typing moves between hands and fingers. Keygen Pro uses a comprehensive rhythm analysis system that categorizes every trigram into one of 29 distinct patterns, providing detailed insights into layout efficiency and typing comfort. Currently, only a few of these 29 categories are displayed, but more comprehensive breakdowns will become available in future updates.
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.
Keygen Pro 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.
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:
Keygen Pro 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. Keygen Pro 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. Keygen Pro accounts for this by providing rhythm stats both with thumbs and without thumbs.