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Systems
Feedback, second-order effects, and things that push back.
- Brooks's lawAdding people to a late project makes it later.Concepts
- Campbell's lawThe more a quantitative indicator is used for social decision-making, the more it will be corrupted — and the more it will distort the process it was meant to monitor.Concepts
- Chesterton's fenceThe rule that you should not remove something until you know why it was put there.Concepts
- Conway's lawOrganizations produce systems that copy their own communication structure.Concepts
- Eliyahu M. GoldrattThe theory of constraints, the five focusing steps, and the critique of local optimisation.Figures1947–2011
- Feedback loopAn arrangement in which the output of a process becomes an input to the same process.Concepts
- Functions, and why subscripts are functionsWhat the arrow in f from A to B means, why every column of a table is a function from a row to a value, and why a subscript is the same thing written differently.Math
- Gall's lawA complex system that works is invariably found to have evolved from a simple system that worked.Concepts
- Goodhart's lawWhen a measure becomes a target, it stops being a good measure.Concepts
- Hofstadter's lawIt always takes longer than you expect, even when you take into account Hofstadter's law.Concepts
- Nested sums, and the loop they describeTwo sigmas side by side are two nested loops.Math
- Parkinson's LawWork expands to fill the time available for its completion.Concepts
- Perverse incentivesAn incentive that produces the opposite of what it was meant to, because people optimize the thing rewarded rather than the thing intended.Concepts
- Process DebtThe accumulated cost of doing things ad hoc.Concepts
- Products, quantifiers, grouping and joinsPi is sigma with multiplication and identical grammar.Math
- Reading a real formulaTaking the revenue formula apart mark by mark, the three checks worth running on any formula of that shape, a set of mixed exercises with no new notation, and a cheat sheet of everything in the series.Math
- Second Order EffectsThe consequences of the consequences.Concepts
- Sets, and why a table is oneThe marks for membership, subsets, size and the Cartesian product — and the one idea the rest of the series rests on: a database table is a set of tuples, which is what the word relational means.Math
- Sigma, and what it is really doingThe summation sign has exactly four parts, and every sigma you will ever meet has the same four.Math
- Systems ThinkingSystems thinking explains an outcome by the structure that produces it — the connections, delays and feedback among the parts — rather than by the properties of the parts.Concepts
- The bottleneckThe single constraint that sets the pace of a whole system.Concepts
- The GoalA system produces at the rate of its single binding constraint, so local efficiency everywhere else creates inventory rather than output.Books1984
- The law of trivialityThat the time a group spends on an item is inversely proportional to its importance.Concepts
- The Peter principleThat people get promoted on performance in their current job until they reach one they are not good at, and then stop being promoted.Concepts