The Cost of Licensing and Certification

In my post "Fisking the NEA's Improvement Ideas", I said that all of the NEA's calls for teacher certification were less about teacher quality and more about increasing the union's power and increasing salaries.  This strategy is as old as guilds from the 15th century.

Here is a study about the American Bar Association and the bar exam and its effects on quality and salaries.

A newly constructed data set on lawyers' licensing exam difficulty, candidate quality and exam results allows to distinguish the alternative theories. Public interest theory is rejected in favor of capture theory. The results imply that professional licensing has a significant effect on entry salaries. On average, licensing increases annual entry salaries by more than $20,000. This implies a total transfer from consumers to lawyers of 36% of lawyers' wages and a total welfare loss of over $6 billion.

Thanks to Volokh for the link.  This same post from Volokh also talks about how lawyers are trying to prevent non-lawyers from performing certain duties, including workers comp hearings and real estate closings.  And don't even get me started on hair braiding.