A predetermined motion time system is frequently used to perform Labor Minute Costing in order to set piece-rates, wage-rates and/or incentives in labor oriented industries by quantifying the amount of time required to perform specific tasks under defined conditions. Today the PMTS is mainly used in work measurement for shorter cycles in labour oriented industries such as apparel and footwear. This topic comes under wider industrial and production engineering. One of such a system is known as "Work Factor" and more popular Methods-time measurement, released in 1948 exist today in several variations and used in some commercial applications. New legislation in developed markets following sustainability issues, Living Wage movement and the 2013 disaster in Rana Plaza, Bangladesh have brought labor costing and standards back to the focus of activists and global fashion retailers. Occupational safety and health, Ergonomics, Skills development and job satisfaction are some of the other factors influenced by Labor Standards Act. PredeterminedMotion Time Standard and Predetermined Time standards, Pre-determined Time Systems are other terms that describe same concept by different authors. Main outcome of PMTS application is quantifying labor inputs in terms of SMV or SAM.
TMU
Most predetermined motion time systems use time measurement units instead of seconds for measuring time. One TMU is defined to be 0.00001 hours, or 0.036 seconds. These smaller units allow for more accurate calculations without the use of decimals. In the most in-depth PMT systems, motions observed will be on the level of individual TMUs, like toss and simple pick-up. More general systems simplify things by grouping individual elements, and thus have larger time values - for example, a bend and arise and one or two steps. Systems with even less detail work with TMU values in the hundreds, like climbing 10 rungs on a ladder or passing through a door. The choice of which variation of a certain PMTS to use is dependent on the need for accuracy in contrast to the need for quick analysis, as well as the length of the operation, the distances involved in the operation, and the repetitiveness of the operation. Longer operations often take place on a larger spatial scale, and tend to be less repetitive, so these issues are often treated as one. For longer, less repetitive operations, statistical analysis demonstrates that the accuracy of less detailed systems will generally approach the accuracy of more detailed systems. Thus, in order to reduce the time required for analysis, less detailed systems are usually used when possible. Conversely, very short, repetitive processes are commonly analyzed with more exact methods like MTM-1 and MiniMOST because of the need for accuracy.
Manchester University researchers including Doug Miller, has gone deep into uses of PMTS in apparel labour costing in "Towards Sustainable Labour Costing in UK Fashion Retail." Doug says ..work measurement for arriving at a standard time should normally make provision for relaxation, contingency and special allowances. According to the International Labour Organization, as of 1992 there were some 200 different PTS systems.
