What Is the Role of Item Response Theory in GAMSAT?

GAMSAT is a standardized exam. The exam pattern is completely different. It is the toughest medical entrance and observes the intellectual skills of candidate. There is no structured material to study GAMSAT. The syllabus and the method are unique for GAMSAT. Even the score calculation is a complicated process.

Students tend to calculate their scores after the exam out of curiosity. In GAMSAT, it cannot be done. The scoring process has been kept confidential by ACER (Australian Council for Educational Research). Nobody knows how the GAMSAT score is being calculated except few people in ACER. It is believed that Item response theory is being used to scale the performance. Still there are unexplored myths in GAMSAT score calculation.

I was curious to know more about GAMSAT score calculation. I researched and collected some information. I would like to share that information. The result says that Item Response Theory (IRT) is being used in calculating the score.

What is IRT?

Item Response Theory is also known as latent trait theory or strong true score theory or modern mental test theory. It is the preferred method for the development of the high-stakes tests such as college entrance examination or medical entrance etc.

It is the study of test and item scores based on assumptions concerning the mathematical relationship between abilities and item responses. It is the advanced form of Classical test theory.

IRT provides more sophisticated information about the response of the item.

Score calculation using IRT:

I would not say that the below are the exact GAMSAT score calculating method. I have tried depicting on my own with the information gathered. Also I know, there is no restriction for guessing games.

Researchers are expecting that Item response theory (IRT) will be used in calculating the score. IRT scoring requires complex estimation procedure. It is very difficult to understand the calculation.

Item Response Theory means focusing on the response of the Item. Using this theory the questions in each section will be evaluated separately. This evaluation will be done based on the difficulty of the question and the response of the candidate.

The IRT curve will be created by modeling the response of the candidate. It measures the given ability to each Item in the test. So the score will be calculated based on the performance of each candidate.

IRT is based on the probability of a correct or keyed response to an item. It is a mathematical function of person and item parameters. This person parameter is called “Latent trait”.

In GAMSAT, each question will be standardized as per its difficulty level. Candidate’s scores are also calibrated on that same difficulty level scale. Then these scores will be scaled into GAMSAT scale of 0 to 10 for each three sections separately.

Initially GAMSAT score will be calculated for each section using the below formula:

GAMSAT section score = (Estimate in logits + 5) X 10

“Logits” is the unit used for calculation in IRT method

The overall GAMSAT score is calculated using the below formula:

Overall Score = (1 x Section I + 1 x Section II + 2 x Section III) / 4

Most of us know the above formula. It is the only formula revealed to us but there are many steps of calculation taken place behind the screen.

IRT is considering the performance of the candidates and the difficulty of the questions. It is the critical method followed to evaluate the GAMSAT scores.

Let us not depend on the calculation. It is good to rely on your preparation. It is important to spend more time on revising previous question papers. I would like to share the benefits of GAMSAT practice tests. It would help you to perform well in your exam.

Source by Mary Anita

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