In practical terms, this means that, as soon as a machine is freed, the shortest job that is ready will begin processing. This minimizes the mean waiting time for jobs from arrival to the start of processing, it also minimizes the waiting time and mean lateness of each job. While this is very efficient, it does not take into account setup times or due dates, which could affect the efficiency of production. Critical ratio is a paradigm that divides the time remaining until due date by the word time remaining on the order. This enables the manufacturer to prioritize those jobs that have the highest intensity in terms of time needed and time available to complete any given job. The highest critical ratio is therefore enjoyed by our Order A, with 6 days of production time and a due date of 11 July. This is followed by Order C, with 8 days of production time and due on 25 July, Order E, with 9 days of production time and due on 29 July, Order B, with 2 days of production...

The FCFS process, for example, does not take into account either production times or due dates. The DD paradigm in turn does not take into account the processing time for each order.
This leaves the SPT and CR paradigms. SPT is efficient in terms of giving priority to those orders that take the least time to complete. Here also, however, due dates are somewhat ignored in favor of shorter processing times. The most efficient paradigm might be said to be the Critical Ratio. This rule takes into account all the important factors inherent in the production process. When working with CR, it is most likely that Hi-Lo will be able to efficiently and completely deliver…