# Understanding and applying Item Response Theory

In the process of designing a quiz application that can assess the student for understanding of a particular concept, I came across Item Response Theory. I have absolutely no clue whether applying this would make my life easy or will complicate further. Till now I''ve been able to find few papers, blogs and also noted a few books on this topic. But I am not able to figure out what should I start with. Any good material to understand what this beast is in layman's terms? Also, it would be great if anyone could help me know what other tools towards similar end can be used.

To help you get started with IRT, consider getting Baker F. B. (2002). The basics of item response theory (2nd ed). You can also get a free download of his software. It is a self-directed learning tool and you might find it quite useful to start your understanding of this field.

As well, to understand IRT with some coding examples there is some material for R around. For example, this wiki for the mirt package contains slides, examples, and exercise files (answered and unanswered) which may be helpful to understand an apply IRT in your research.

I agree with @philchalmers that the mirt package is a great place to start, as it is well documented and has many examples online. Additionally, I would recommend the a visual guide to item response theory slide deck, as well as Bonifay (2019) - a good introductory text, and Bock & Gibbons (2021) - a text for the more advanced user (though it is still quite accessible!). Finally, I agree with @doug.numbers that Baker's book is a good reference. However, if they are referring to Baker & Kim (2004), it should be noted that it is quite technical, as it focuses primarily on parameter estimation$$^1$$.

$$^1$$ For a more accessible introduction to IRT parameter estimation see Wirth & Edwards (2007).

References

Baker, F. B., & Kim, S. H. (2004). Item response theory: Parameter estimation techniques. CRC press.

Bock, R. D., & Gibbons, R. D. (2021). Item response theory. John Wiley & Sons.

Bonifay, W. (2019). Multidimensional item response theory. Sage Publications.

Wirth, R. J., & Edwards, M. C. (2007). Item factor analysis: current approaches and future directions. Psychological methods, 12(1), 58.