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TOC Part 1 - Theory of Constraints

When I first heard about the Theory of Constraints in 1997 I was curious about it. I read "THE GOAL" and thought, well it seems reasonable, but hardly surprising. Then I read "CRITICAL CHAIN" and then started thinking is that all there is?

To be honest about it, from a project scheduling point of view there is not much more to it than a resource loaded critical path method (CPM) schedule with a certain amount of strategically placed contingency tasks. I was underwhelmed. To top it off, the concepts are wrapped in a second-rate novel. Um... OK. I just didn't see why anyone would care particularly much about a repackaging of existing concepts. Then I learned that Mr. Goldratt had his own institute. An institute with $10,000 Jonah programs. It got me thinking of L. Ron Hubbard.

But misgivings aside, it was clear that I was headed for a collision course with TOC. I'll cover that in some upcoming postings.

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Comments (3)

I'm not a TOC fan for much the same reasons. But I have clients who are, so I've looked at most of the materials. On the shop floor and in the planning offices of aerospace, buffers are used to provide explicit margin (reserve) for critical path items. In many contracts these explicit margins must be show in (green) on the monthly report. We manage this margin in the weekly status meetings, handing it out and deducting the amount from the reserve.
What strikes me about TOC is two things --

-- There is a force of personality behind the "theory" in TOC. This is a powerful incentive be "get behind the idea."
-- It is unique enough and slightly non-obvious to require some work to both understand and practice TOC.

On the shop floor (my experience was in furniture manufacturing) it works as long as the process flow set up in the same way - build the shop around TOC (which they did). I was tasked with deloying an ERP system against this process flow, which turned out to be difficult 'cause SAP doesn't work like TOC, of KANBAN or anything else except SAP.

The real trouble I have is that the proponents are such zelots for TOC that engaging them in a sensible discussion is difficult through the narrow pipe of email and BLOGs. Much like the early days of XP, the force of personality is carrying the ball. We'll have to see if the proof turns out to be the same as the theory. I've been wrong before - who in their right mind would pay $2.51 for a cup of coffee???

Jack:

Glen,

I agree. I'm about to cover some of the disadvantages of the approach for certain situations - as I get time. I think that zealotry gets in the way of many things.

The problem I have with zealotry and other rules-based approaches is that project management (among other things) is about making the most out of what you have. Sometimes you have tortillas and avocados. It would be senseless to try to make them into potato soup.

Joël Séguin:

Can't wait to read the rest, Jack...

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