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the goal
as far as i can tell, there is no universal definition of the word "goal" in the toc literature. as a working definition, let's define "goal" as the object/aim of an action.
"What is the real goal? Nobody here has even asked anything that basic. "
The Goal, ch. 5
productivity
productivity is anything that moves the system closer to its goal.
"Every action that brings a company closer to its goal is productive. Every action that does not bring a company closer to its goal is not productive."
The Goal, ch. 4
throughput accounting
"Throughput is the rate at which the system generates money through sales."
The Goal, ch. 8
dependent events & statistical fluctuations
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vanity metrics
"So what?"
The Goal, ch. 25
the utilization of a non-bottleneck is determined by some other constraint in the system, not its own potential. abstracting the principle, activity is not progress. e.g., how often have you seen metrics such as more sales calls, website visitors, software features, employees kept busy, more projects started, or in other words, thinking that local optimization improves the system as a whole, but it does not!! observe the following: a system with three stages A, B and C, where the capacities are A = 100, B = 60 and C=90. the whole system can complete only 60 units. suppose you improve A from 100 to 120, well nothing changes (globally), the local metric improved but the system is deteriorating. in fact, throughput remains constant but inventory increases, then "so what?" the reason local optima is not global optima is because the parts are dependent, which usually is the case in any business. the principle is also easy to prove with convex analysis.
bottleneck
"What you have to do next, Alex, is distinguish between two types of resources in your plant. One type is what I call a bottleneck resource. The other is, very simply, a non-bottleneck resource."
The Goal, ch. 18
inherent simplicity
"The first and most profound obstacle is that people believe that reality is complex, and therefore they are looking for sophisticated explanations for complicated solutions. Do you understand how devastating this is? "
The Choice, ch. XX
go deep. ask why, why, why, why, why and do not stop at the first one. we expect the problem to branch by having one cause split into multiple ones and each of those splitting in to several more causes. but, the physical world does the opposite, the system converges, i.e., "common causes appear as we dive down." getting to the base or the root cause that governs the entire system is the result of asking why a few times.
a second obstacle to not understanding the concept of "inherent simplicity" is that we tend to accept conflicts as given. Goldratt has a great way of looking at conflicts, treat conflicts like the scientist treats contradictions. for instance, the proper scientist would never say "let's average the contradictions out and move on," but instead seeks to remove the underlying assumption that causes the contradiction. similarly, any conflict between two people is held together by some assumption that is false. Do not seek to compromise, it does not work, find the false assumption and remove it.
circular logic
"So the key to thinking clearly is to build logical maps. You start with an effect, any effect, and dive down to the root causes by asking, ‘Why does the effect exist?’"
The Choice, ch. 14
imagine someone tells you that 'the shop under-orders because the owner is conservative.' well, how do you know he is conservative? because he under-orders. notice that it feels like an explanation because it contains "because," but it is in fact only circular. it rewards you with the feeling of understanding but giving you nothing of substance. so, how do we tell a real "because" from a circular one? the technique of Goldratt is to first understand that a real cause never produces only one effect, e.g., if the owner is conservative then this single cause sits under many effects. so instead of trying to verify the cause directly, predict a second effect the same cause would produce.
the six questions of technology
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