Moving away from the field exercise, it is often more convenient to test a theory by reducing the level of personnel involvement. Map exercises can be conducted involving senior officers and planners, but without the need to physically move around any troops. These retain some human input, and thus can still reflect to some extent the human imponderables that make warfare so challenging to model, with the advantage of reduced costs and increased accessibility. A map exercise can also be conducted with far less forward planning than a full-scale deployment, making it an attractive option for more minor simulations that would not merit anything larger, as well as for very major operations where cost, or secrecy, is an issue. (This was true in the planning of OPERATION AI.)