Is The MRP Algorithm Fatally Flawed?

(Links updated Feb 24, 2010)

Robert Johnston, now at the University of Melbourne   holding the John Skarkey Chair of Information Systems and Organisation at the UCD School of Business in Ireland, did his PhD work at Monash University in Australia. His dissertation, “The Problem With Planning” presents a thought provoking thesis.

– Early robotics and computational intelligence models were built on a model which research at MIT debunked as unworkable in the 1980’s.

– The MRP algorithm uses the same model.

– Therefore, MRP is also unworkable.

Further, his dissertation goes on to postulate that the successful models currently being exploited by the latest research at MIT (which, by the way, are commercially exploited by the Roomba) share many similar characteristics with kanban systems.

I will extrapolate a bit and comment that kanban systems are a subset of a general shop floor information management model that is outlined in “Decoding the DNA of the Toyota Production System” by Spear and Bowen. Johnston’s work pre-dates Spear’s publication, so it is not referenced, but if you actually read Spear’s dissertation you can see the similarities in the details.

And yes, when I wrote to Dr. Johnston his first comment back was surprise that someone had actually read his dissertation. Take a look. Chapters 1-5 are mostly theoretical background and history. The interesting part starts at Chapter 6.

The Essence of Just-In-Time

The Essence of Just-In-Time

This is a working paper by Steven Spear of Harvard Business School. Spear’s PhD work was summarized in a landmark and well-circulated Harvard Business Review article titled “Decoding the DNA of the Toyota Production System.” I will leave it to the reader’s Google savvy to turn up the DNA article for yourself.

This working paper is much more raw than a finely edited HBR article. But it gets to the core research and conclusions without any fluff.

As you read it, compare what is described here with the focus of your own implementation.

Do you find any gaps?

I’ll comment more myself when I am not totally jet-lagged… I just got back from China. 😉

The Essence of Jidoka

SME: The Essence of Jidoka – dead link

You can download it here.

This link is to an article I wrote for the SME online “Lean Directions” site back in 2002. I am including it on this site for the sake of completeness. I noticed that the Wikipedia article on the same subject is largely derived from this, which I simply consider flattery.