Ceteris Non Paribus

Ceteris Non Paribus is my personal blog, formerly hosted at nonparibus.wordpress.com and now found here. This blog is a place for me to put the ideas I have, and the stuff I come across, that I’ve managed to convince myself other people would be interested in seeing. See the About page for more on the reasons why I maintain a blog and the origin of the blog’s name.

My most recent posts can be found below, and a list of my most popular posts (based on recent views) is on the right.

Ceteris Non Paribus

What makes a country great?

I had a chance to stop in Salima and Senga Bay over the weekend, to see a friend of mine from the Malawian Army who is headed to Ivory Coast to join a peacekeeping force there. While there I got to thinking about national greatness. One thing many Americans point to when asked what makes America a great country is its natural beauty. But Senga Bay is just one example of the stiff competition Malawi puts up in that department:

I’m not writing this just to show off the sweet pictures I took of the beautiful place I stayed (okay, it’s partly about that). I also want to make the point that my friend the peacekeeper exemplifies how Malawi’s greatness is exactly the opposite of America’s. Beyond our amber waves of grain, Americans are raised to be proud of their country’s martial tradition. When I was a kid I learned we had never lost a single war out of the many we had fought, and that we had single-handedly defeated Hitler and Imperial Japan. It was only much later that I learned about Vietnam and the war of 1812 (most American still insist that we won the latter, which was a sideshow to the Napoleonic wars in which the British razed our capital), and also about the crucial role played by Stalin’s Russia in stopping the Nazis.

The accuracy of the narrative aside, a history of aggression and warfare is a very primitive thing to rest one’s national pride on. And we certainly do – despite our country being founded by a set of brilliant intellectuals, we mainly remember the one who led our army, and focus on his military accomplishments rather than his political acumen. Malawi’s military history is a stark contrast to our own. To the best of my knowledge, the army’s only non-peacekeeping engagement was an intervention in Mozambique’s civil war in the 1980s. Zero wars in fifty years of existence is an impressive track record.

Instead, their army has been engaged in keeping the peace in other countries. Sometimes war is necessary, but peace, peace is worth being proud of.

A pre-emptive eulogy for Fanta Passion

One of the many pleasant surprises I encountered on upon arriving in Malawi last year was learning that the country’s markets stock Passion-fruit flavored Fanta, which is arguably the greatest soda in the world. I’ve always been fond of passion fruit juice, and when I discovered it came in soda form (back in 2004, in Tanzania) it was love at first sight. It doesn’t hurt that Passion Fanta mixes quite nicely with Konyagi, a Tanzanian liquor that I mainly came across in what are basically ketchup packet shots.

If last summer was a happy reunion, then this summer so far – foreshadowed by my week-long visit in April – has been a slow, painful farewell. Passion Fanta is stocked out (“finished”, in Malawian English) virtually everywhere and almost no one seems to know quite why. In Lilongwe, other than the dregs of past crates still available in a very few restaurants, it’s been relegated to the back of a single shelf at Spar:

What happened to my favorite soda? One theory advanced by a clerk at Metro Cash & Carry is that Fanta Passion sells out fast because it’s more popular than the other flavors – he said they got 100 crates of the stuff last year (that’s 2400 bottles),and it’s all gone now. While this flies in the face of basic economic theory (high demand should lead to a larger quantity traded in the market, not lead to stockouts) it’s consistent with stuff I’ve read in the past about why certain items (bananas, t-shirts that fit a regular human) always sell out first.

A major hindrance in tracking down the source of the shortage is that I’m not even sure where exactly Fanta Passion comes from. Fanta is famously obtuse about which flavors are available where, probably because most are made by local franchisees. Passion fruit flavor is, as far as I know, found only in this part of Africa; it used to be in Australia and allegedly was a promo flavor in Brazil. The bottles themselves are no help at all; they are reusable glass with no markings of an origin.

My working theory, based on conversations with wholesalers, is that Fanta Passion is being made in Tanzania and was previously imported into Malawi, a trade that was screwed up by foreign exchange shortages. The only shortcoming of this theory is that it makes no sense: Fanta Passion flowed like water last year at the height of the foreign exchange crisis, and now, with forex relatively plentiful, it’s gone. Another option is that the trade just wasn’t smart business. All flavors of Fanta sell for the same price (even now, with Passion almost extinct); why offer Passion, which costs you far more to transport to the point of sale, when the Orange flavor is made in Malawi?

Lies everyone tells about higher education

Everyone knows that the cost of college has skyrocketed over the past few decades, and also that it’s better to take classes taught by tenure-track faculty and a damned shame that all these fricking TAs are leading sections. It’s just common knowledge. Kevin Carey of the New America Foundation’s Education Policy Program tells us what we already know in this interview on NPR’s Fresh Air. (NB: I’m on Malawian cell-phone internet right now so I just read the article and can’t listen to the actual recording, but the article is mostly verbatim quotes from Carey).

Unfortunately, neither of these facts are particularly backed up by the evidence. The latter point is kind of weird to begin with: have any of the people bemoaning the rise of lecturers in teaching actually taken any classes taught by faculty on the tenure track? Adjuncts and lecturers are hired for, and evaluated on, their teaching. I’ve had almost uniformly good experiences in their classes. Tenure-track professors, on the other hand, are paid for and focused on their research. Some are amazing teachers, especially for graduate-level courses, but back when I was an undergrad I had lots of professors who were awful teachers. Carey even admits as much later in the article, so why make this hackneyed complaint about adjuncts? If we want to improve higher education, one place to start would be to give this much-maligned group credit for being the dedicated and highly-qualified educators they are, rather than deferring to the archaic status system of academia.

But costs are definitely rising, right? I wouldn’t be so sure: the alleged increases of inflation + 4% are the sticker price of college, not the cost people actually pay, which includes grants and financial aid. Those prices have been rising far slower than the sticker price, and for private universities have actually fallen in nominal terms, according to this graph (ironically taken from a different NPR article which I found via Susan Dynarski):


That doesn’t include room and board, but financial aid can help with those ancillary costs as well. Assuming I’m reading it properly (the article is sparse on details) then the true price of college has risen slower than inflation and has actually fallen in real terms for both public and private schools. That’s very different from the take you typically get in stories like the Carey interview.

The only downside to this positive trend is that not enough people are aware of how much financial aid is available to them, and often the worst-informed prospective students come from the poorest families. It does them a major disservice to harp on the huge and rising costs of a college education without also noting that very few people pay full price. One reason for America’s poor college attendance figures is that while people understand the payoffs to a degree, they overestimate the costs. This hits disadvantaged students the hardest – they stand to benefit the most from financial aid and tend to understand it the worst – but even the well-off need help figuring out what college actually costs and learning how to work the system in their favor. One of my dad’s businesses focuses on coaching students and their parents through the college application process, and the area where people consistently need the most help is in understanding costs, financial aid and scholarships.

Hat tip: My mother, via email

One in five

HIV may be harder to measure than anything else we study in public health and social science. It is largely invisible to the naked eye, its transmission is low-probability and highly variable, and perhaps most importantly, people have strong incentives to hide their status and avoid testing. These incentives arise from everything from stigma to a desire to maintain access to sex partners to a perception that HIV testing is just a death sentence, with tests highly likely to be positive and bringing no benefits. We’ve gotten a lot better at measuring things like the prevalence of the virus, but even now our estimates have to be taken with a grain of salt.

Despite all that, we do have a decent sense of how common it is in different regions of the world. In urban Malawi, which includes the place I’m currently sitting, the answer is that a little over 20% of the population has the virus. For historical reasons, those rates are typically computed for the population aged 15-49, so the overall rate might differ, but that’s still a decent range for prime-aged adults (and indeed there’s no reason to think the prevalence drops drastically above that age range). HIV takes around ten years to lead to death, with visible AIDS lasting for something like one year. So as a basic estimate, 20% of people are carrying the virus, but just 2% would be visibly ill. That second number is small enough to ignore, so about one out of every five people in Lilongwe is infected with HIV.

This is a nearly-incomprehensible figure for me. Sometimes if I pass through crowds I try to imagine that every fifth person I pass has an incurable virus (although many don’t know it). I honestly can’t do it – they all look like regular people to me, because that is exactly what they are. But all the evidence I’ve seen indicates that people here do manage to wrap their minds around the idea that one in every five people in the street (or one in every five potential sex partners, or one in every five people on their soccer team) is infected with HIV. I have no idea how they manage it, either psychologically or in terms of making important life decisions about stuff like whom to marry. People often wonder what an economist is doing studying HIV prevention. The answer is that the choices people make about sex and marriage in the face of HIV constitute what I would argue is the hardest – and the most interesting – decisionmaking problem in the world.

High dispersion in inflation rates

Last night I met a former hotel employee who hand-calculated inflation figures for the region around his resort, using year-on-year price changes for the official consumer price basket. He came up with an annual inflation rate (if memory serves) of 28%, which is nearly two and a half times the official Reserve Bank of Malawi figure of 11.4% (as of March).

I’m really surprised that the local rate would be so much higher than the national one, since a lot of the goods in the basket are fairly tradeable. I don’t, however, suspect that things are being intentionally gamed: I know lots of folks who currently or formerly worked at central banks and even interned at one myself, way back when, and they’re uniformly well-intentioned data geeks like myself. But this is a way bigger spread than we see, for example, across US regions, so I’m at a loss to explain what’s going on.

Out with the new

I spotted this sign of renewal on my way out of Kamuzu International Airport:

That’s the original Malawi flag, featuring a red, rising sun. The late President Bingu wa Mutharika changed it to a new version with a white sun in the middle in 2010, in a widely unpopular move that allegedly cost on the order of twenty million dollars.

The BBC reports that the Malawi parliament voted to change the flag back to the red-sun original in late May of this year, but that the new President, Joyce Banda, still had to sign the bill into law. I can’t find any confirmation online that she actually did so, which is a pattern common to many news stories in Malawi – there’s often just an initial report, and no followup. But I’ve seen it with my own eyes, which is good enough.

As an added bonus, I’ve heard that the change back won’t be nearly as expensive: all they have to do is take the pre-2010 flags back out of storage.

Why I'm back

This post marks my triumphant return to the blogosphere after a too-long hiatus from writing over at MethodLogical. Why? In short, I’ve found myself wanting my own independent forum to store my thoughts and throw up links to cool stuff and pictures of what I’m up to. This is all detailed in the about page, which I will quote wholesale because no one can stop me:

  This blog is a place for me to put the ideas I have, and the stuff I come across, that I’ve managed to convince myself other people would be interested in seeing. It also serves as a way for folks who care what I’m doing (hi, mom!) to keep track of what I’m up to when I’m on another continent or otherwise out of touch. I’ve done stuff like this in the past, but my previous blogs have been trip-specific (Jason Does India) or joint efforts with other people (Positive Impact Institute, Methodlogical). This time, it’s a solo effort, and one I intend to last. That means that I am aiming a bit lower – at one-off opinions without tons of research or effort, rather than the kind of thorough, thoughtful analysis that the bloggers at Development Impact put up each week. In this I am inspired by Chris Blattman’s thoughts on staying power and blogs. He was probably being facetious when he said that “sometimes I even read part of the papers I reference”, but in my posts here I may do that quite literally. Carefully thinking things through what my day job is for (sort of – I’m a graduate student, but the point still stands); this blog is intended for stuff that’s just a bit too highbrow for facebook. “Ceteris Paribus” is Latin for “other things equal”, and is the implicit assumption in all causal analyses. Suppose I observe groups A and B, seeing that group A does X while B does not, and therefore deduce that the different outcomes in A are attributable to X. This is true so long as ceteris paribus holds – if X is the only difference between the groups. Scientists can use randomized experiments to ensure that all else is in fact equal, but in the absence of an experiment it is almost always the case that ceteris non paribus: tons of other stuff is going on. I’ve named my blog after my obsession with this basic inferential error, because, while people make it everywhere, my research areas (public health and development economics) are especially plagued by failures to hold all else equal. Articles on Yahoo! News treat people who don’t drink red wine as a valid comparison group for people who do, and find all kinds of spurious health benefits. NGOs and advocates select the best schools located closest to roads for a pilot intervention, then tout the big advantage in test scores between the intervention schools and the rest of the country. 90% of my academic work boils down to saying “not so fast – what’s your comparison group?”, and one major purpose of this blog is for me to vent my frustrations about people constantly getting it wrong.

Who am I? If you’re reading this then you probably already know me, but you can still check out one of those false-third-person biographies here.