Erotustarkkuus

Erotustarkkuus, a Finnish term, translates to "discrimination accuracy" or "discriminatory power" in English. It is a statistical concept primarily used in the context of psychometrics and educational testing. Erotustarkkuus measures the ability of an item (such as a question on a test) to differentiate between individuals who have high overall ability or knowledge and those who have low overall ability or knowledge.

A high erotustarkkuus indicates that the item is effective in separating these two groups. Typically, items with high erotustarkkuus have a positive correlation with the total score on the test. This means that individuals who score well on the item are also likely to score well on the overall test, and conversely, individuals who score poorly on the item are likely to score poorly on the test.

In test construction, items with low or negative erotustarkkuus are often problematic. A low positive correlation might suggest the item is too easy or too difficult for most test-takers, failing to distinguish between different levels of ability. A negative correlation suggests the item might be measuring something different from the intended construct, or it might be poorly worded, leading high-ability individuals to answer it incorrectly and low-ability individuals to answer it correctly.

Erotustarkkuus is a crucial metric for item analysis, helping test developers refine their assessments by identifying and revising or discarding ineffective items. It contributes to the overall validity and reliability of a test by ensuring that its components accurately measure the intended trait or knowledge domain.