Part 3 · Decision 7 · Weeks 12, 14

"Whose work goes first, and how does it all connect?"

When you have more work than capacity, sequence is everything — the same five jobs can finish in half the time depending on what runs first. And when an operation grows past a couple of people, the only way to keep it coordinated is a system that talks to itself. This is the last decision in the course: how to sequence work, how to manage the constraint, and how to wire everything together with ERP and IoT.

SPT · EDD · CR Theory of Constraints ERP & IoT

Why this decision matters

Scheduling is the most under-taught piece of operations because it feels small. It isn't — in a job shop, the choice between SPT (shortest first) and EDD (earliest due date first) can change average lateness by a factor of three on the same workload. The Theory of Constraints scales that intuition: the only place sequencing matters is at the bottleneck, and elevating the bottleneck (Goldratt's Five Focusing Steps) is how throughput actually grows. ERP is what makes any of this scale — one source of truth across finance, manufacturing, sales, and HR — and IoT is what gives ERP its real-time eyes.

By the end of this topic you'll be able to

Apply SPT, EDD, and Critical Ratio to a small job list and defend which rule wins on which metric (makespan, average lateness, average flow time). Walk the Five Focusing Steps on a real constraint. Explain what an ERP system does, why most implementations are painful, and where IoT data plugs in. Tie all of it back to the integrative bakery story.

Materials

Key concepts to know
  • Priority rules — SPT (shortest first) minimizes average flow time; EDD (earliest due date) minimizes maximum lateness; CR (critical ratio = days remaining ÷ work remaining) balances both.
  • Makespan — time to finish the entire set of jobs.
  • Johnson's rule — optimal two-machine sequence for minimizing makespan.
  • Theory of Constraints (TOC) — the system's throughput is set by one constraint. The Five Focusing Steps: Identify, Exploit, Subordinate, Elevate, Repeat.
  • Drum-buffer-rope — the constraint sets the drum (pace), a buffer protects it, the rope pulls release rate to match.
  • Throughput accounting — throughput − truly variable cost = contribution; decisions optimize for constraint contribution.
  • ERP — one integrated system across modules (finance, HR, manufacturing, sales, supply chain). Single source of truth.
  • IoT in operations — sensor data feeding ERP and analytics; the real-time eyes on the operation.
Class notes & cheat sheets
Bedtime stories — scheduling & ERP through narrative

Both stories are available as printable docx and as interactive web versions.

Hands-on activity — sequencing the fulfillment log
Practice with games · Scheduling, TOC & ERP
Using AI on this decision

Scheduling is one of the cleanest demos of AI strength: paste a job list with processing times and due dates and ask the model to sequence under each rule and report makespan, average flow time, and average lateness. It will compute all three in seconds. Where it stumbles: when sequencing depends on tooling changeovers or worker skill — you have to explicitly model those constraints.

For ERP, AI is mostly a writing assistant — summarizing module choices, drafting requirements, comparing vendors. A useful prompt: "given these business processes, which ERP modules will I actually use and which will sit unused?"

Working alongside AI also changes which human skills matter most. Try:

Self-check (Part 3 review — covers Topics 6 & 7)

Choose docx or interactive game format.

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