Most economists have to significantly reduce the complexity and finer details of the economy through a set of reality crushing assumptions in order to make their models work coherently. See the artist's depiction of how an economist thinks below.
Then again, the really harmful economists are relatively unconstrained by reality in the first place, and can freely draw their conclusions and make policy recommendations basic on gnostic wisdom received from the ascended masters of malarkey.
This has given rise to a priori based models, spawned by well-funded think tanks and other hired servants of Big Money, about the way markets work. The economies they describe are evidenced only in an incorporeal universe of the economist's fevered imagination, and have been rarely seen in the real world.
Nevertheless, there are whole schools of thought that engage in herculean attempts to erect an homage to their particular madness out of well-tortured statistical bones. Some recent examples are the efficient markets hypothesis, free trade, supply side economics, and the infamous trillion dollar platinum coin that solves budget problems at a single 'clink.'
As a rule of thumb, the more arrogant certainty with which the economist states their revelations, and the more reliant they are on jargon and assumptions that suck the reality out of the room like intellectual black holes, the less space there is likely to be between their hat and their ass.
