The Purist

There are many different schools of thought in operations management and within each we often find the purist. Two such purists would include the Enterprise Resource Planning (ERP) purist and the Lean Manufacturing (LM) purist. According to Merriam Webster’s dictionary, a purist is:

“One who adheres strictly and often excessively to a tradition; especially: one preoccupied with the purity of a language and its protection from the use of foreign or altered forms.”

These two philosophies (e.g., ERP and LM) have very different traditions, thus very different ideas of how to implement. It is therefore very logical that an ERP purist and a LM purist would be at odds with one another.

ERP purists adhere to … Planning horizons, schedule stability, data accuracy (bills of material, inventory, etc.), push systems, detailed shop floor control and transaction processing, and variance analysis.

The bottom line from ERP is that double digit inventory turns are possible (based upon cost of goods sold). Ten turns in most industries are not only achievable, but are considered exceptional if demonstrated. Customer service levels can be risen and shortages eliminated (once how to manage dependencies are learned).

LM purists adhere to … Eliminating waste, continuous improvement, value stream mapping, factory floor layout, kanban pull systems, and simplification.

The bottom line from LM is also a double digit inventory turn, but considerably more than ten. Because LM is primarily an execution system, it requires a longer range planning system. Most LM purists will at least agree to keep the ERP system for long term planning. This planning however is not tied to execution.

The problem with the “purist” in either case is that they want to discard all other philosophies and operating models for their “pure” approach. John Costanza of the JIT Institute was the first such purist I ran across back in the 1980’s. John’s viewpoint was simply, “you cannot evolve from an ERP company to a LM company. It takes radical redeployment.” I am often in the company of purists from both sides.

As a consultant, I often follow LM purists in several organizations. As the ERP guy, my job is usually to figure out what can be done to salvage the ERP system after such a visit. Using an ERP analogy, a lean purist often behaves like an ERP consultant that only knows a few of the modules. He implements what he believes to be correct for those modules often at the cost of the other modules. Those of us with ERP experience know that this does not work well in the ERP world. It does however suggest that overall business objectives (short, middle and long term) must be considered in any implementation.

Many LM purists come from manufacturing engineering positions and many do not understand the internal workings of the ERP system. This type of purist is very much like the MRP analogy above.

While a great deal of my career has been learning, implementing and teaching other organizations how to implement ERP systems, I do not consider myself to be a purist. Instead, I adopt a “best of breed” approach. It has been my experience that ERP works better (and often easier) when implemented with LM concepts, especially that of continuous improvement. ERP alone is a good tool, but when combined with LM, or the Theory of Constraints (TOC), it is a much better tool. There are concepts in all three of these major manufacturing philosophies that can be used in both internal and external supply chains.

On the other hand, I do get defensive when confronted with a LM purist that claims ERP does not work. ERP would not have survived as long as it has if it didn’t work. The reality is that many ERP organizations are looking to LM for improvement, yet can’t “throw the baby out with the bath water.” In the short term, ERP needs to stay functioning as it is the core business system. Over the long term, dependency on the ERP system can be reduced, or even eliminated. The largest hurdle seems to be overcoming an accounting system based upon transactions. If the transactions that drive the accounting system are no longer performed, how will we drive accounting? This means that any LM implementation, in a company that uses ERP (which most do) must account for this transition.

I believe in a holistic approach. Whatever the strategy and/or tactics employed, they must be congruent with the corporate direction. Implementing technology in any one area must therefore not prevent the success in another. Purists often seem to forget this as well.

What do you think?