Markets & Economics.

Small repeated changes build on everything that came before.

Adding one more input can produce less extra output than the one before.

Choosing one useful thing means giving up another useful thing.

A contribution can benefit the whole group while costing the contributor.

Paying the second-highest bid changes the incentive to report your value.

The highest estimate may be the one with the largest upward error.

When buyers cannot observe quality, good products can leave the market.

A shared project succeeds only after enough people contribute.

Try to predict what others will predict, not a number's intrinsic value.

Two sellers compete for customers spread along one street.

More items in a stable process usually means a longer time spent inside it.

Small customer changes can become larger swings in upstream orders.

A more efficient tool can increase total resource use if demand expands enough.

A small fraction can account for a large share when values have a heavy tail.

Owning an item can change the price at which someone is willing to give it up.

An inferior third option can change how two original options are compared.

Early adopters and imitation can create an S-shaped adoption curve.

Spending more effort raises your chance of winning but everyone pays their effort cost.

Having an edge is one thing. Knowing how much to bet is another.

When a measure becomes a target, it can stop being a good measure.

Some things become more useful when more people use them.

When someone acts on your behalf, whose interests are they serving?