The zoo is one of the metaphors used in the book “Thinking in Systems” by author Donella Meadows (1941-2001) and one of my favorite takeaways from her book.
Told in my way, the zoo is a convenient way to observe animals that would not be that easy to observe in their natural habitat. In a zoo animals are usually grouped by families, fenced-off from one another, fed, and given care. This makes the observation convenient for visitors but isn’t truly reflecting the usual behavior of the animals.
When antelopes graze quietly and offer the visitors the opportunity to watch them at will, it’s because the predators are kept away, food and water is provided. In their natural habitat, the antelopes would be on constant watch for danger, run away if sensing anything threatening or roam the land looking for their food and water. A very different behavior than the one in the zoo.
The same happens when observers look on parts of a system and draw conclusions about what they saw when the system was in a specific state that eases the analysis. It isn’t the real system’s behavior when interactions with other parts are cut off or aren’t taken into account. It’s like looking to the antelopes protected from their predators, the fence and zoo arrangement cutting-off the dynamic interactions that otherwise take place in their real habitat.
The conclusions about antelopes observed in the zoo would turn out to be far from what is observed in the savanna. Hence the zoo-based observation is largely unfaithful, incomplete, biased and potentially misleading compared to the observation of the antelopes in their real habitat. Nevertheless, the zoo visit is convenient and allows to gather a lot of knowledge about the animals.
To me, the zoo metaphor is a strong reminder that looking at static parts of a complex system, overlooking or ignoring the dynamic interactions with other components does not represent the true system.
And as convenient the partial and static view is, it should not be used to draw general conclusions about the whole system.
That is probably why many improvement initiatives on the shop floor fail to deliver noticeable results at the company (which is the system) level. A Value Stream Mapping (VSM) is a great way to pinpoint local wastes and improvement points, but only on a part of the system and in a given set of circumstances.
VSM are usually drawn for some product families only and the situation observed is assumed to be representative of the process usual behavior, just like the antelopes in their zoo enclosure.
As long as wannabe Lean Thinkers keep visiting their zoo, chances for real, meaningful and sustainable improvement will remain low.