the first generation of pmt systems, mtm1, were very finely detailed, involving much analysis and producing extremely accurate results. this attention to detail was both a strength and a weakness, and for many potential applications the quantity of detailed analysis was not necessary, and prohibitively time -consuming. in these cases "second generation" techniques, such as simplified pmts, master standard data, primary standard data and mtm2, could be used with advantage, and no great loss of accuracy. for even speedier application, where some detail could be sacrificed then a "third generation" technique such as basic work data or mtm3 could be used.