My favorite post from the comments section:

Anybody who thinks a study is needed to answer the question of whether a minimum wage costs jobs, is an idiot. I get the political hacksterism behind the debate, but really the only response needed to PK is “Liar!”
It isn't that laypeople would be idiots, but any economists who claims as much are indeed being idiots or liars. The reason is that the most foundational theory of economics is supply and demand. At its core is the statement that if the cost of a good increases, the demand decreases. This has been demonstrated to be true in every testable instance. It is as known to be true as having a bucket with ten apples and adding five apples to it makes the bucket have fifteen apples. Rilla once mentioned some research and theory about how higher costs can induce increase in demand, which is true, but those are different than the supply curve theory. Example: even though engagement diamonds only have value because of their high price, the supply curve still applies to any increase or decrease in the price. A change in perception of a good based on price can change the demand for good regardless of how the supply curve operates on it. So, you can have a good that increases in demand if the price goes up in the way that engagement diamonds are a thing because of the desire for only expensive diamonds, but this is due to a fundamental change in the perception of the product, not because of a negation of the supply curve.

So yeah, economists know beyond any doubt that increasing the cost of labor decreases the demand for labor, and thus results in increased unemployment. They wouldn't even bother wasting tons of money and time trying to demonstrate this in studies if it wasn't for some of them having a political axe to grind. A more indepth look at the dynamic can produce all sorts of caveats, like how if prices are increased 1/1 then employment doesn't increase, or that if the value of labor undergoes a fundamental perception shift due to its increase in cost (extremely, utterly, vastly rare). But the bottom line is the supply curve is correct and every economist on the planet knows the most direct effect of minimum wage is more unemployment than otherwise.