The sign tax

Interesting observation from The Beautiful Tree:

We told [the researchers] to comb every street and alleyway in urban areas, visit every village and settlement in the rural surrounding areas, looking for private schools. Be warned, we said, they won't necessarily have signboards advertising their existence: in Nigeria, there is a hefty tax on signboards, so school owners often prefer to go without.

Thus a fundamental truth is revealed: when something is taxed, expect to get less of it. If you tax payrolls, you get fewer jobs. Taxes on sales will reduce the number of items sold. Taxes on income mean reduced salaries. Taxes on businesses mean fewer companies. The list goes on.