The advantage of using a measure comprised of multiple questions versus a single question is that it allows us to gather information on a particular concept using a multi-dimensional approach. We also know that measures are more reliable when they include a number of well-formulated questions, as this allows us to more accurately differentiate between students.
For example, a reliable measure will allow us to differentiate between students with high versus low levels of anxiety. Using a measure that is reliable will also ensure that if we were to ask students to respond to the same questions at a later date their responses would be similar.
Read our Items, Measures, and Constructs article to learn more.