Is the items too difficult or too easy for the candidates Can it distinguish between the knowledgeable student and a student who is not Whether the distracters are functioning as expected or have they failed in their task

In order to answer these questions, the educators need to perform an item analysis and this would be rather useful in preparing MCQ banks for the future use as it would give the best and the most reliable set of test items for the educators to work with.

There are several theories behind the procedures adapted in doing an item analysis and among them ‘Item response theory’ is widely used in the modern time.

Item response theory

In the item response theory, it is believed that, the performance of an individual in relation to a particular test item would have a correlation with the persons performance as a whole based on his or her latent trait which would decide the persons overall ability.

As such, the theorists have formulated three parameters that needs to be assessed with regard to a test item and these include,

-Difficulty – The level of ability that requires answering a test item correctly

-Discrimination – Ability of a test item to separate candidates with similar abilities

-Chance – The probability of a candidate guessing the answer correctly than based on the ability

http://www.helium.com/items/1881131-psychometrics-in-education-overview-of-item-analysis