An item data entry task has 10 items with two incorrect values. What is the error rate?

An item data entry task has 10 items with two incorrect values. What is the error rate?

• A. 10%
• B. 20%
• C. 0%
• D. 5%

Answer: (B)

Error rate is the proportion of items that contain errors relative to the total number of items. With ten items and two items having incorrect values, the rate is 2 out of 10, which equals 0.2 or 20%. If both incorrect values were in the same item, the rate would be 1 out of 10, or 10%. The other options would only be correct under those different scenarios (no errors would be 0%, and 5% would imply half an item is incorrect, which isn’t how item errors are counted).

Error rate is the proportion of items that contain errors relative to the total number of items. With ten items and two items having incorrect values, the rate is 2 out of 10, which equals 0.2 or 20%. If both incorrect values were in the same item, the rate would be 1 out of 10, or 10%. The other options would only be correct under those different scenarios (no errors would be 0%, and 5% would imply half an item is incorrect, which isn’t how item errors are counted).