Linda, absolutely! I didn't particularly want to go there, but I was thinking of that rule as I was writing this. So 46 year old men can look for partners as young as 30, 30 year old men look for partners as young as 22, etc. US data has precise ages rather than age categories (it is unbelievably easy to work with!) so it would be quite easy to work out the size of the potential partnership pool using the American Community Survey, say (did I say how easy US data is to work with? That's the subject of another blog post!).

David, the height study contains good, credible evidence that S. Korean heights have increased substantially in the past 50 years. What is far less credible is the idea that heights were increasing rapidly between 1896 and 1916, long before S. Koreans started drinking milk and eating substantially more meat etc. But those years between 1896 and 1916 are generating a good chunk of the growth in height that is reported by the article - and in the popular media.

Nick - thank you! I think this is why, even though we disagree on so many things (politics, cities, gas bbqs) we write WCI together - we agree on this, which is pretty fundamental.

Gene - "But if no one had TP, would it really make it a less just and sustainable world?" I've got some flak on Facebook for not discussing the fact that much of the world uses water rather than TP. I think that, for women, absence of TP is a problem in an urban environment and with modern Western clothing - I'd give up a lot of things (kitchen towel, for example) before I'd give up TP. (Men can shake off these difficulties in a way that women can't.) On the other hand, before going to Inner Mongolia I spent 5 days walking in Wales, happily popping squats behind bushes etc - found that much easier than the gas station toilet in Inner Mongolia.

Hugo: "so perhaps there exists in these cities a high TP eq. for the upper echelons of society and a low TP eq. for the less fortunate." Very probably - but to the extent that that's possible, it's symptomatic of social segregation - i.e. the less fortunate don't get near the places where abundant TP can be found. Inner Mongolia is kind of the Saskatchewan or Alberta of China, right down to the grasslands and the museum full of local dinosaur finds. Like the prairie provinces it's been doing fairly well recently with agriculture, mining, fossil fuels etc - I didn't do a lot of shopping because prices there are higher than in the UK. But even in the trendy coffee shop that could be lifted right off of Bloor St there was no TP.

Brad, interesting comment. Some of the overall gender gap is due to a few people, who are mostly men, vastly out-earning everyone else - your (1). But they don't really pop out in the data I could find here http://www.statcan.gc.ca/pub/11f0019m/11f0019m2013347-eng.pdf or Tammy Schirle's work here. On group 2 - there's always this http://marginalrevolution.com/marginalrevolution/2016/07/what-are-young-men-doing.html. But basically because there's lots of different sub-marriage markets, and a lot of the action in the marriage market is happening when people are in their 20s and 30s when earnings are changing rapidly, it's hard to say definitely one way or the other.

rsj: "With AirBnB, people complain when long term rental units start being displaced and long term owners find that they are suddenly living in busy hotel districts instead of quiet residential districts." Hotels are facing the possibility of a major hit to their bottom lines as their busy hotel districts get turned into half-full hotel districts. Long-term owners and renters in quiet residential districts just aren't that affected because quiet residential districts are, overwhelmingly, not desirable as Airbnb locations. Think, e.g., of Rosedale or Hyde Park or even Trinity Bellwoods in Toronto, Burnaby or Coquitlam in Vancouver, Alta Vista in Ottawa, Garrison Woods in Calgary - these places just aren't that attractive as Airbnb destinations, because they're not walking distance from the downtown scene, museums etc. Yes, sure, there are probably some downtown condos where owners are up in arms over Airbnb in rentals - but they would also be up in arms over empty units, rentals to students, rentals to people with yappy dogs, etc. My view is that by far the most plausible source of fuss over Airbnb is a major industry that's strongly effected by it. Re your point on zoning arbitrage: given that zoning can contribute to urban sprawl (e.g. Ottawa) and social segregation (e.g. every city that curtails the inflow of lower income residents by banning or restricting basement suites, imposing minimum lot sizes, etc), I'm not convinced that a bit of zoning arbitrage is such a bad thing.

Avon, vitamin D fortification was introduced to protect children. Vitamin D is required for healthy bone and other types of growth. Past experience has shown that, absent fortification, not all parents will ensure that their children receive adequate levels of vitamin D, either through exposure to sunlight, eating cod liver oil, or in other ways. Markets require fully informed economic agents to achieve efficient outcomes. Children cannot be assumed to be fully informed and rational economic agents. There's your market failure.

Henry: "Is the regulation explicitly targeted at certain ethnic groups with certain skin pigmentations or is it targeted towards all Canadians?" The regulation applies to all milk sold in Canada, but it was introduced in 1965, which is probably the point in time where the percentage of people in the population who were lactose intolerant was lower than it has been at any time before or since. So it's not in any sense explicitly targeted at certain ethnic groups. However the optimal level of vitamin D fortification, and the best way to deliver that fortification, is likely to depend upon the ethnic and cultural composition of the society (and, in a country like Canada, also on the geographical distribution of the population north/south).

Avon - "but it runs against most people's sense of fairness" Poking holes in utilitarianism is easy. The challenge - as the GBA+ folks have found - is coming up with some kind of alternative. Can you articulate a little bit more precisely what "fairness" means to you? That, too, will be normative. Because what we're doing here is having a normative discussion about the best way to organize the world. Which is perfectly fine. That's what WCI is for.

Avon: "Thus, the allocation that maximizes society’s total utility has the less productive members having higher overall utility than the more productive members. Do we really want this? Even little kids recognize that merit should be rewarded." And bureaucrats do too. Any attempt to maximize social welfare has to take into account the relevant constraints. A key constraint on tax/benefit policy is that the tax/benefit scheme should not make it attractive for high ability individuals to masquerade as low ability individuals. I.e. the tax/benefit system should not be so redistributive that highly productive people quit their jobs as computer analysts on Wall Street and instead become part-time math tutors living at home in their parents' basements. But that's the kind of thing that can happen if the tax/benefit system is designed so that less productive members had higher overall utility. This is why there are real limits to the amount of redistribution that social welfare maximizing bureaucrats and policy analysts advocate. I would have expected you to have gone with a rights-based critique of utilitarianism. I.e. not that utilitarianism is impractical, but that it's morally wrong because focuses only on the ends (how happy people are) rather than the means (due process, respect for human rights and dignity, etc). Nozick, Wilt Chamberlain, etc.

Formerstudent - yup - and that's a huge data gap! Admin data would pick up some sex changes, but those still enforce gender binaries. Saul Templeton, http://law.ucalgary.ca/law_unitis/profiles/saul-templeton is starting to do some interesting work that's related to this area. See, e.g., his blog posts (linked to from his web site).

Luis - what kind of perspective are you looking for - mainstream, feminist, development econ,....?

Jacques Rene - it would be really interesting to compare maternity/parental leave taken by self-employed women in Quebec/ROC. I wonder if anyone has done that. Sick leave is also an issue - I have a friend who is self employed and having some health issues and it's totally brutal because no work=no income, Frances

Angella - interesting. That doesn't look like it's specifically for EI claimants, though, and I don't know if there's anything that encourages people to sign up. I'm thinking of things like this reporting calendar - http://www.esdc.gc.ca/en/reports/ei/calendar.page - wouldn't it be possible to make that a little bit sexier and also encourage people to use is to do thinks like keep track of networking, reaching out for contacts, etc? People must have turned their mind to this....

Vladimir - was just looking that up today for the EI claimant in my household. Here's the clawback info: http://www.esdc.gc.ca/en/reports/ei/repayment.page. It starts at net income around $63,000, and people who haven't claimed in the past 10 years are exempt from the taxback. Remember the regular benefit/contribution ratio for the construction industry is more than twice the Canadian average. The clawback will make a bit of a difference, but it's still way out of whack.

Just embarrassed by my carelessness....

Kevin, thanks for this. May not have a chance to correct this for a little while - see how the morning goes tomorrow. It is clearly differentiated by being in red on the spreadsheet, but I didn't read the footnotes. Sorry about that.

Avon - "There is little reason to think that a government monopoly is any better than a private one." Or any worse - Beer Store v. LCBO is a case in point. Competition matters much more than ownership.

Bob - Has anyone looked at the economics of converting the DVP into a toll road? I wonder who the winners/losers would be? My first worry would be that it would just divert the traffic onto streets around there, thus be an inferior policy to a congestion charge. On toll roads: it's the cost of land that I'm talking about here when I'm talking about the subsidies to toll roads. I remember once hearing a story (which may or may not be true) that a land developer once came to the City of Toronto and offered to build an express tunnel underneath the harbour to replace the Gardiner Expressway in exchange for the land that the Gardiner Expressway is on. What did the developers of the 407 pay for the land that road lies on?

Ryan, and I personally really enjoy driving the 407 - allows me to completely avoid Toronto rush hour traffic when driving from Ottawa to Waterloo. I also like going to the opera. And in a way toll roads (at least in our present system) are like opera - they provide really nice things for people who are able to pay for them, with significant subsidies that come in part from people who aren't able to pay for them.

Kelvin - I wondered if it was that. So it's partly the funding story, partly the self-government story, i.e. that Vancouver and New West had greater power to say no, and partly the self-interest story, i.e. that the highway wouldn't have shortened the commute from Shaughnessy downtown materially.

Erik - o.k., I take your point on SoCreds in Vancouver. But that then raises the question - why did the funding formula so penalize the city of Vancouver and New West? Perhaps Vancouver votes were too expensive to buy with roads, because of the cost of building roads within the city? Or perhaps Vancouver voters just didn't fancy roads all that much? Look at that highway map and think what's in it of a typical Point Grey resident - basically nothing. Perhaps a slightly faster drive to the ski hills on Saturday morning, but there wouldn't be any traffic to speak of on a Saturday morning anyways. When you talk about the failure of central coast megaprojects - is this a good thing or a bad thing? I'm thinking LNG, for example.

Jacques-Rene - thanks for writing - we haven't had a chance to chat for a while. I didn't know about Quebec City - thanks for the link.

Mike - Whenever I drive the Don Valley I'm torn between thinking "it's so terrible that what could be a beautiful urban wilderness is desecrated by this roadway" and thinking "this is such a fast way to get downtown" (I don't usually drive it in rush hour). So, yes, when freeways work they're pretty sweet. The question is: if road users had to pay a toll that reflect roads' actual cost, how much would people still use the highways? I think I'm right in saying that the new toll on the Port Mann bridge has affected traffic volumes much more than the provincial government expected. And the 407 is pretty empty. I'm not disagreeing with you about the value of road tolls - just pointing out that, if we actually charged tolls that approximated the economic costs of roads, we wouldn't be building a great many freeways.