What method is primarily used to test a trainee's ability to recall and label parts of images?

The method primarily used to test a trainee's ability to recall and label parts of images is labeling. This technique focuses on assessing a student's understanding and memory by requiring them to identify various components within an image and accurately assign labels to each part.

Labeling tests are effective in educational settings, particularly for visual learners, as they integrate imagery with applied knowledge. This form of assessment engages the trainee actively with the material, reinforcing their retention of information related to the images they are working with. It requires not just recognition but the retrieval of specific terms or concepts associated with the visual elements, making it a strong tool for comprehension and recall.

In contrast, the other methods like completion, essay, and true or false have different purposes. Completion questions typically ask for a short answer to fill in a blank, essays require longer, more in-depth responses, and true or false questions test recognition rather than recall. Therefore, labeling is the most direct approach focusing on recall and labeling parts of images.