Performance of on-line lot sizing heuristics with a worst-case ratio of two

Research has shown that for the economic lot-sizing problem, the on-line heuristics PPA and H* are amongst the best performing heuristics on the test bed by Berry (1972). Both of these heuristics have a worst-case ratio of 2, which is the lowest value possible for heuristics in the class of on-line heuristics. This might raise the presumption that the possession of a worst-case ratio of 2 is a good property for an on-line heuristic to have. We shall do this by modifying some well-known existing heuristics in a way that gives them a worst-case ratio of 2, and then comparing their performance against the performance of the original heuristics using the test bed by Simpson (2009).