The imminent release of transgenic cotton brings with it the need for some changes in production techniques to provide effective refuges as part of the pre-emptive resistance management strategy (see papers by Fitt and Forrester, this proceedings). Refuges are clearly the most unusual aspect of the strategy. Here we briefly describe our work to quantify the value of different types of refuge for Helicoverpa where the chief measure of value is the number of moths produced per unit area overtime. A refuge which produces twice as many moths is twice as valuable for resistance management, all else being equal.