What is the primary purpose of using cross-validation?

The primary purpose of using cross-validation is to prevent overfitting of the model used in research. Cross-validation is a statistical method employed to assess how well a model generalizes to an independent dataset. By partitioning the data into subsets, the model is trained on a portion of the data and validated on another, which helps to ensure that the model performs well on unseen data, rather than just memorizing the training dataset.

This technique is crucial, particularly in complex models that might fit the training data too closely, capturing noise rather than the underlying data structure. By evaluating the model's performance on different segments of data, researchers can gain insight into its predictive validity, thereby reducing the risk of overfitting and ensuring that the findings are more robust and replicable in real-world applications. This focus on maintaining model generalizability is central to the rigor of psychological research methodologies.