Errors cost more than one keystroke
A mistake can require noticing it, stopping, reaching for Backspace, reorienting the eyes, and rebuilding rhythm. That interruption is often more expensive than the original key.
Net speed and correction count expose this cost better than raw WPM alone.
Accuracy creates predictable rhythm
Consistent correct transitions reduce the need for visual checking. Once the movement is trusted, speed can rise without conscious effort on every character.
Use strict practice selectively
Strict practice is useful when a repeated wrong movement needs to be interrupted. It should not replace all natural typing, because real work also includes correction and recovery.
When to increase speed
Increase pressure after accuracy remains stable across several sessions, the hands stay relaxed, and the same keys no longer dominate the weakness report.