Of the one-time methods, a mail survey, which this article recommends, has many advantages. It leaves a paper trail and generates a wealth of data that can be compiled and analyzed in a number of different ways. A survey can pose complex questions, such as asking respondents to rank replies. Disadvantages include a time element of several months from design through distribution through analysis; the recommended cost of hiring of an expert to guide the survey through these different stages; printing and postage costs; and the fact that not everyone will respond.