2013-08-06
Explanation
The comic pokes fun at macroeconomics and its predictive limitations. In the first panel, someone asks whether macroeconomics is a science. The response is that it is a social science, meaning it is not as precisely predictive as a hard science like chemistry. The questioner then asks how macroeconomists make all their predictions, and the economist replies that they use certain techniques, though some are more reliable than others.
The punchline comes in the final panel, labeled "Earlier," which reveals the economist stirring a cauldron while chanting something like "Eye of newt and wing of flea, what is next year's GDP?" This is a direct parody of the witches' scene from Shakespeare's Macbeth, where the witches brew potions and make prophecies. The joke is that macroeconomic forecasting, despite its academic veneer, is essentially no better than witchcraft or fortune-telling.
The votey (bonus panel) shows a magic 8-ball-style response reading "2% higher... +/- 7%," reinforcing the joke that macroeconomic predictions are so imprecise (with error bars far larger than the prediction itself) that they are essentially useless. This is a common criticism of economic forecasting: the margin of error often dwarfs the actual forecast, making the prediction meaningless in practical terms.