The primary purpose of a scaled score is to achieve which of the following?

A scaled score primarily aims to improve comparability across different test administrations, which is essential for ensuring that scores remain consistent regardless of variations in the test format or difficulty. This means that scaled scores allow educators, administrators, and stakeholders to make fair comparisons of student performance over time, even if the specific items on the test change.

While stability of measurement over time is also an important consideration in assessment, the main focus of a scaled score is to ensure that scores can be reliably compared across different contexts and populations. In this way, scaled scores provide a meaningful interpretation of a student's abilities and performance, which is vital for educational decision-making.

The option regarding the calculation of the dispersion of a data set does not apply to the purpose of a scaled score, as scaled scores are not designed to represent variability but rather to provide a consistent metric. Similarly, a single overall score is a byproduct of the scaling process, but the primary intent is to enable meaningful comparisons rather than just yielding one score.