[en] The decay rate is calculated of an Alfven or plasma surface wave propagating along an inhomogeneous layer of plasma. The inhomogeneous profile is thin and odd, but otherwise arbitrary. The wave's decay rate is determined using two fundamentally different methods, the integral-differential equation approach of Sedlacek and the Fourier expansion technique of Cally, and found by both to depend only on the slope of the Alfven or plasma frequency profile at the ^resonant point^, and not on other details of its shape. The result is verified numerically. This problem represents a good example with which to compare and contrast the two methods. (author) 3 figs., 7 refs