Understanding the Conversion of Raw Score to Scaled Scores in CAT

The Common Admission Test (CAT) is a standardized examination conducted by the Indian Institutes of Management (IIMs) to select candidates for their respective MBA programs. The process of converting raw scores to scaled scores is critical to ensuring fair and accurate evaluation of candidates. While exact details have not been provided by the IIMs, the scoring process follows an industry-standard psychometrically-sound approach as implemented by Prometric. This article delves into the methods used to convert raw scores to scaled scores in CAT.

Raw Score Equating

The initial step in the CAT scoring process is the equating of raw scores. Equating is a statistical process that involves adjusting scores on two or more alternate forms of an assessment so that the scores can be used interchangeably. This ensures that the scores are comparable, regardless of which form of the test was administered.

Industry-standard equating processes are used, as outlined within the ETS Standards for Quality and Fairness. The purpose of this process is to ensure that the scores are fair and accurately reflect the candidate's performance. It is particularly important in tests where different questions may have varying levels of difficulty or wording.

Scaling to a Common Metric

Following the equating process, the raw scores are further adjusted through a scaling process to a common metric. Scaling is necessary to provide an appropriate interpretation of the equated raw scores, ensuring that scores are comparable and meaningful.

A linear transformation is used for the scaling process, which is an industry-standard practice. This transformation is based on specific models outlined in A Test Equating, Scaling, and Linking: Methods and Practices by Michael J. Kolen and Robert L. Brennan.

The IIM CAT Scaled Scoring Model

The IIM CAT employs a unique scaled scoring model. This model ensures that each section and the overall score are appropriately measured and compared. The scaled scores are presented as follows:

Section Scores: Ranges from 0 to 225 Total Exam Score: Ranges from 0 to 450

Three scaled scores are presented for each candidate:

An overall scaled score Two separate scaled scores for each section

Conclusion

The process of converting raw scores to scaled scores in the CAT is a critical step in ensuring fairness and accuracy in the evaluation of candidates. By following industry-standard methods for equating and scaling, the IIMs maintain high standards of quality and fairness in the CAT.

For more detailed information on the CAT scoring process, refer to the following sources:

A - Test Equating, Scaling, and Linking: Methods and Practices (Statistics for Social and Behavioral Sciences) Standards for Educational and Psychological Testing The ETS Standards for Quality and Fairness

Understanding these concepts can help candidates and educators prepare more effectively for the CAT and interpret the results accurately.