the geh statistic is a formula used in traffic engineering, traffic forecasting, and traffic modelling to compare two sets of traffic volumes. the geh formula gets its name from geoffrey e. havers, who invented it in the 1970s while working as a transport planner in london, england. although its mathematical form is similar to a chi-squared test, is not a true statistical test. rather, it is an empirical formula that has proven useful for a variety of traffic analysis purposes.