Posted by Austin Fossey
In my last post, I explained the function of a content review committee and the importance of having a systematic review process. Today I’ll provide some suggestions for how you can use the content review process to simultaneously collect content validity evidence without having to do a lot of extra work.
If you want to get some extra mileage out of your content review committee, why not tack on a content validity study? Instead of asking them if an item has been assigned to the correct area of the specifications, ask them to each write down how they would have classified the item’s content. You can then see if topics picked by your content review committee correspond with the topics that your item writers assigned to the items.
There are several ways to conduct content validity studies, and a content validity study might not be sufficient evidence to support the overall validity of the assessment results. A full review of validity concepts is outside the scope of this article, but one way to check whether items match their intended topics is to have your committee members rate how well they
think an item matches each topic on the specifications. A score of 1 means they think the item matches, a score of -1 means they think it does not match, and a score of 0 means that they are not sure.
If each committee member provides their own ratings, you can calculate the index of congruence , which was proposed by Richard Rovinelli and Ron Hambleton. You can then create a table of these indices to see whether the committee’s classifications correspond to the content classifications given by your item writers.
The chart below compares item writers’ topic assignments for two items and the index of congruence determined by a content committee’s ratings of the two items on an assessment with ten topics. We see that both groups agreed that Item 1 belonged to Topic 5 and Item 2 belonged to Topic 1. We also see that the content review committee was uncertain on whether or not Item 1 measured Topic 2, and we see that some of the committee members felt that Item 2 measured Topic 7.
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