What are standardized tests primarily used for?

Standardized tests are primarily used for measuring individual differences because they are designed to assess and compare the performance or abilities of individuals under uniform conditions. These tests provide a structured way to evaluate various traits or skills such as intelligence, aptitude, or personality characteristics, allowing for quantitative comparisons across different individuals or groups.

By using set procedures for administration and scoring, standardized tests ensure that results are consistent and reliable, which is crucial when making decisions related to education, employment, or psychological assessment. This capability to quantify differences among individuals positions standardized tests as one of the key tools in both educational and psychological contexts to evaluate how individuals stand in relation to a defined population.

The other options, while related to methodologies in psychology, do not accurately capture the primary purpose of standardized tests. Qualitative data is generally gathered through methods such as interviews or open-ended questions, observational data relies on behavior observations, and interviews primarily aim at gathering personal insights rather than standardized scores.