The GCTE validation of soil erosion models for global change studies

Take a hammer! It may be used (or misused) to bang in nails and tacks, as a crowbar or lever, and for many other things. Now imagine that you are selecting a hammer for use in some odd job. You probably would not just grab whatever hammer happened to be closest to hand. Instead, you might first pick one or two from your toolbox and check that their heads are secure and their handles straight, and maybe even make a few experimental swings. Now, if you knew something about the work to be done, you would select a hammer of about the right size. OK, but what if you did not know in advance what the task might involve? Well, most probably you would take along a few hammers, big and small, light and heavy, long and short, and then—once you knew more about the work—use that which you judged to be the best suited. An obvious strategy? In the development, exploration, and use of runoff and soil erosion models, the generally adopted methodology has not usually involved any such explicit consideration of ‘experimental design’ (as it has become known in other areas of science and …