The kinds of typing errors

Not every typing error is the same. The site logs four kinds. Knowing which kind you make most often will tell you what to drill.

Substitution

You meant the, you typed tge. The wrong key was the right one's neighbor.

Substitutions are the most common typing error and the easiest to fix. They mean your finger went to the wrong column. Two letters that look adjacent on the keyboard often have different fingers assigned, so a substitution suggests a finger drifted.

The fix is reach drills. Open Stage 4 -- Reach drills and run the drill for the hand that produced the substitution. If you cannot tell which hand, run both.

Transposition

You meant the, you typed teh. Two letters in the right place, but in the wrong order.

Transpositions usually mean one hand is faster than the other, and the slow hand is being passed by. The fix is rhythm: type at a pace your slower hand can keep up with.

If the transposition happens with the same hand (e.g., s and a swapped, both on the left), the fix is different. That is a finger-fight, where two fingers reached at the same moment and the wrong one landed first. Slow down for ten seconds; the issue almost always resolves.

Omission

You meant the, you typed te. A letter is missing.

Omissions are the worst kind of error because they are the hardest to notice. The cursor still moves; the word looks plausible at a glance. Most omissions are recovered after the next word, when you re-read and find the gap.

Omissions usually come from a single finger that did not register. Either the keystroke was too light to trigger, or the finger lifted before it pressed. Both happen on tired hands.

The fix is to take a break. Omission rates spike near the end of long sessions. If your last 100 chars have three omissions and your first 100 had zero, you are tired. Stop.

Doubling

You meant the, you typed tthe. The same key registered twice.

Doublings come from key-bounce on certain keyboards, or from a finger that pressed slightly too long. Almost always a hardware artifact, not a technique problem. Some keyboards have configurable key-repeat delay -- if doublings happen often, slow your repeat delay.

If they happen on a specific key over and over, the key may be wearing out. Common on heavily-used letters: e, t, a, n.

Reading the chart

The character report on the stats page lists every character by error rate and average ms. Sort by error rate descending. The top of the list shows your worst characters.

Look at the surrounding letters. If your worst character is t and your second-worst is g, you have a left-index problem. If your worst is h and your second is n, right index. The pattern usually points to a single finger that needs work.

A final note

Errors are noise. A 3% error rate is normal. A 6% error rate is high and worth investigating. A 10% error rate means you are typing faster than your fingers can sustain, and the fix is to slow down.

The number that matters most is not the error rate on any single session. It is the trend across many sessions. If your error rate is dropping over weeks, your practice is working. If it is rising, something has changed -- new keyboard, new posture, fatigue.