Choose the quantity to solve, then enter the required values to calculate an error percentage, words-per-error ratio, word error rate (WER), or Half Total Error Rate (HTER). HTER averages two rates at one threshold; it does not locate equal error rate.

Error Rate Formula

For a running record, the following formula gives words per error. Error percentage instead uses TE / TW × 100.

ER = TW / TE

Where ER is words per error (the total-words / total-errors ratio)
TW is the total words
TE is the total errors

Divide total words by total errors for words per error. With zero errors this ratio is undefined, while error percentage is 0%. Conventional errors:words notation places 1 first, for example 1:10.

Error Rate Definition

What is an error rate? In a running record, words per error is total words divided by errors. Error percentage is errors divided by total words, multiplied by 100. Label the ratio orientation clearly when scoring a running record.

Example Problem

How to calculate error rate?

First, determine the number of words read.
For this example, the student read 500 words.
Next, determine the number of errors.
While reading, there were 50 recorded errors.
Finally, calculate the error rate.
Using the formula above, words per error = 500/50 = 10. This is words:errors = 10:1, or errors:words = 1:10; the error percentage is 10%.

About Error Rate?

What is the error rate used for? An error rate, in this case, is a measure of the rate of errors of a student while learning. This rate is used to assess the learning or educational level of a student when conducting a running record.

What is a running record? A running record is a reading assessment tool used by teachers to analyze how students or readers are performing at reading. This is a type of fluency assessment since the reader must be reading aloud.

When to use running records? Running records are typically used for young students that are still learning how to speak a language properly to determine their fluency with said language.