What is a Carroll diagram?

Transcript A Carroll diagram is an alternative to a Venn diagram that we use when we’re sorting using two sorting rules simultaneously. So, for example, you might be sorting numbers and wondering if they’re even but also if they’re two-digit numbers.

Now the way a Carroll diagram works is that there are two rows and two columns. When you look at the first column and the second column, you’ll see that the second column is the opposite of the first. So if the first column were “even,” the second column would be “not even.” When you look at the two rows, you will notice that the second row is the opposite of the first row. So if the first row were “even,” the second row would be “not even,” if it was the rows that were “even and odd” instead of the columns.

And as I mentioned it’s an alternative to a Venn diagram where we also sort with two rules: Do they fit in this circle, do they fit in this circle, do they fit in both, do they fit in neither? So there, too, there are four sections.

So I mentioned, for example, sorting numbers. We might sort numbers up to 30, deciding whether they’re even or not even, deciding if they’re two-digit or not two-digit. This is how we would fill the Carroll diagram out. Listing the numbers in each of those four cells, and you can see how closely it matches what you do with the Venn diagram. When we list those four sets of numbers in four sections of the Venn diagram.