Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In statistics, benchmarking is a method of using auxiliary information to adjust the sampling weights used in an estimation process, in order to yield more accurate estimates of totals.Suppose we have a population where each unit k has a "value" Y(k) associated with it. For example, Y(k) could be a wage of an employee k, or the cost of an item k. Suppose we want to estimate the sum Y of all the Y(k). So we take a sample of the k, get a sampling weight W(k) for all sampled k, and then sum up W(k)xY(k) for all sampled k.