Although many educational and psychological tests are labeled as computerized adaptive test (CAT), not all tests show the same level of adaptivity -- some tests might not have much adaptation because of various constraints imposed by test developers. Researchers have proposed some indices to measure the amount of adaption for an adaptive test. This article shows some limitations of the existing indices. A new index of adaptivity is proposed in this article. Its performance was evaluated in a simulation. The results show that the new index was able to overcome some of the limitations of the existing indices in the simulated scenarios.