Extrapolation is the process of extending a trend into the future, or of applying the results of a sample to an entire population. For example, a historical trend of 10% gains in sales for the last five years could be extrapolated into the future at the same rate. Or an auditor could extrapolate a 2% invoice error rate from a sample to the entire population of invoices. Extrapolation has a relatively high risk of generating incorrect results, since it assumes that the current data points are recurring, which may not be the case.