The difference from control test is classified as an overall difference test. It is similar to the degree of difference test, in that it is used to determine if there is, in fact, a difference between one or more test samples and a control. And, more importantly, if there is a difference, its size can also be measured with this test.
This test is most useful in situations such as quality assurance and control, where there is a heterogeneous quality to the products being tested.