Mark’s justification for prohibiting unlicensed persons from doing plumbing needs a little more unpacking, though it wasn’t the point of his post. First, some nice words about plumbers: I don’t have the citation, but I read somewhere that if you separate the drinking water from the sewage, which is precisely what plumbers do and what most of the plumbing code provisions are designed to assure, you double life expectancy from 35 to about 70; adding all of medicine’s wonders gets you maybe another five. (Pipefitters do stuff like gas, steam, and chemical, um, pipefitting, which is all good but off the topic here.)
Framing licensing laws as prohibitions is important: nothing obliges Joe to have a plumbing license or any other kind of a license. Actually, in most jurisdictions, you don’t even need such a license to do plumbing as long as it’s in your own house. That prohibition is against occupying the house unless you got a permit to do the work, with an inspection by the city, an inspection that applies also to all work by licensed plumbers and in principle makes the license redundant.
So subsequent buyers of houses owned by reasonably handy people are not protected by licensing requirements but by a different complex of convention and law, including not just inspections and permits but also the difficulty (owing to thread and pipe sizes, for example) of putting plumbing parts together wrong, the evidence of defect typically corrected with a mop and noted with profanity, and the wide availability of pretty good “how-to” books and TV programs. Clerks at hardware stores used to be part of this web of quality assurance but times change and Lowe’s/Home Depot floor staff apparently have some completely different function. The brevity of their moments of visibility in this universe so far has made it impossible to discern what this is.
I’m not entirely a libertarian about this, definitely not ready to sweep away all professional licensing: inspectors can’t always see everything. But we certainly do too much of it. Let’s remember that forbidding unlicensed plumbers to do plumbing as paid work for others is motivated at least in part by its very salutary effect on everyone inside the tent (licensed), keeping prices high by suppressing competition. Getting the state to force your competitors out of business is like actually out-competing them to gain market share, but cheaper, and you get to do it in nice clothes, in fancy restaurants in the state capital, instead of under someone’s house in Carhartts on Sunday. The ghost of the late great Mancur Olson here reminds us that the members of such groups are few, have high stakes in policy, and know who they are, while the rest of us are diffuse, many, and have low per capita stakes. Guess who wins? Many trades, like the fellowship of suers, pleaders and briefwrights, have even arranged for the members of their group to be the sole judges of who can join their legally protected monopoly and on what terms, which is not just rent-seeking but bumper-harvest rent-gathering.
Tilting the pinball machine of business one’s own way is why hairdressers and manicurists often exhibit such a powerful drive to protect the public in this way, and why people who have not yet succeeded in getting these protections enacted for themselves often gin up alternate paths to the same end, like requiring certain jobs in government to be held by people with this or that degree (planners and teachers, for example) or using union membership similarly.
I must at this point clarify the precise scope of the foregoing argument lest our readers be misled. For extremely arcane but absolutely incontrovertible reasons (much too technical to actually explain here, please keep reading right along, thank you) three and only three professional identities completely satisfy the most rigorous theoretical and empirical standards for very strict licensing, namely architects, engineers, and university professors. Maybe college professors, if they behave in a deferential fashion and pay some extra dues. To even consider that just anyone be permitted to wield the sacred instruments and mysteries of these three callings is to invite Really Bad Stuff Happening, I shudder at the thought, wow, what a nightmare. Everyone else, line up to have your market entry restrictions reviewed from scratch, please.