CHAPTER 22

Priority Rule Race

Pick a sequencing rule, see how it changes flow time & lateness, then try to beat it yourself.

Controls
1 Pick a rule below and hit Apply
2 Compare the metrics on the right
3 Switch to Manual and drag rows to beat it!
📋 Job Queue
JobProc. TimeDue DateSlack
💼 Interview Tip

SPT/SOT minimizes average flow time — this is a classic exam & interview question. But SPT can starve long jobs, so real shops often combine it with a lateness cap. EDD minimizes maximum lateness. Be ready to explain when each rule is best and the trade-offs involved.

Instructor Notes
  • SPT minimizes average flow time and average WIP (Little's Law). EDD minimizes maximum lateness.
  • Have students screenshot their best manual schedule and explain the trade-offs.
  • Click New Jobs for fresh data sets; race in pairs for lowest average lateness.
  • Ask: Why might a bank use FCFS even though SPT is "optimal"? (Fairness!)
📊 Schedule (Gantt)
Total Flow Time
Avg Flow Time
Avg Lateness
OrderJobProc.StartEndDueFlowLate
💡 What does this rule do?

Select a rule and hit Apply to see how it works.