It has long been the goal of many researchers to measure the effects of the extraordinary technical improvements in computing markets. Yet is has been very difficult to place an economic value on such improvements. One means for doing so measures a buyer's satisfaction with a product, or "buyer's surplus" -- the difference between what a buyer was willing to pay and what he actually paid. A proper measure of buyer's surplus provides an index of the value to users from a cheaper system or a technically more proficient system. What has prevented research on surplus in the computer market is a absence of sufficiently detailed data on the micro- behavior of computer users. This research will fill this gap. It will develop and use a detailed and rich new data set containing about 70 percent of all medium to large computer users in the United States. A related goal of this research is to shed light on the many factors influencing the diffusion on new computer equipment. Since much technical improvement is embodied in new generations of hardware, the economy can only benefit from technical advance when that new generation of equipment is purchased. This research will approach these issues as questions about the factors underlying the demand for computing. It will analyze the factors determining the decision to adopt technically advanced computing equipment.