Category: Science

Readability and the Writer’s Diet

I read this abstract, laughed a bit, then entered it into The Writers Diet. Try it.

I wish science abstracts, especially those dealing with human impact, and climate change is a huge human impact, were written with specific emphasis on readability and the big picture.

I will read the paper, as well, sounds interesting. The title is “The Optimal Carbon Tax and Economic Growth” – Exciting! But I could not let the abstract go unshared.

In a calibrated integrated assessment model we investigate the differential impact of additive and multiplicative damages from climate change for both a socially optimal and a business-as-usual scenario in the market economy within the context of a Ramsey model of economic growth. The sources of energy are fossil fuel which is available at a cost which rises as reserves diminish and a carbon-free backstop supplied at a decreasing cost. If damages are not proportional to aggregate production output, and the economy is along a development path, the social cost of carbon and the optimal carbon tax are smaller as damages can more easily be compensated for by higher output. As a result, the economy switches later from fossil fuel to the carbon-free backstop and leaves less fossil fuel in situ. This is in contrast to a partial equilibrium analysis with damages in utility rather than in production which finds that the willingness to forsake current consumption to avoid future global warming is higher lower under additive damages in a growing economy if the elasticity of intertemporal substitution is smaller bigger than one.

via OxCarre: The Optimal Carbon Tax and Economic Growth.

Update: Now, to type in some of my paper abstracts into Writer’s Diet and see what happens. I plopped in three abstracts from papers I published for my PhD, you guessed it, all FLABBY!

Helen Sword, the originator of this test has a couple of books on writing that are worth checking out, especially the one called “Stylish Academic Writing”

Update: Via Boing Boing, an article at the Huff Po on how to read abstracts.

Numbers, policy and advocacy

I got into a twitter discussion with Andrew Leach, who writes thoughtfully about energy policy and economics at his blog and occasionally for the globe and mail. The topic of discussion was a number put up by Bill McKibben of 350.org stating the following:

By some calculations, the tar sands contain the equivalent of about 200 parts per million CO2

Now this was a throwaway line in an article warning us that the Obama administration was not doing anything to stop runaway carbon emissions from coal and petroleum. But Prof. Leach made the point that this was a bit dishonest because at the current (and future) rate of oil extraction, it would take over 1500 years, and was  ridiculous. But let’s look at the calculation itself. 200 ppm seems like an outrageously large number. After all, the current concentration of CO2 in the atmosphere is 393 ppm. Is Bill McKibben actually saying that the taroilsands (I can’t pick on tar vs. oil, and I will campaign for taroil) can contribute half of what’s currently in the atmosphere? That can’t possibly be true. I mean, it is a huge project and all, but still, only 6.5% of Canada’s emissions in 2009.

But, if you follow the mathematics:

  1. 1.75 trillion barrels of bitumen in place , as opposed to the 10% of that deemed recoverable in 2006 assuming 2006 prices and current technology.
  2. One Barrel is approximately 0.5-0.7 metric tons CO2 if you take into account both the production and the combustion. Note that there is a lot of uncertainty in this estimate because most of the data come from the Canadian and Albertan governments, and from the producers themselves, very interested parties. Let’s use the 0.7 for an upper end.
  3. 2.13 GT Carbon emitted adds 1 ppm of CO2 to the atmosphere.

This gets us to approximately about 160 ppm. Note that the 0.7 MT of CO2 uses a number for land use that takes into account the current devastation of the boreal forest and peat bog. If all the oil needs to get out of the taroil sands, the land use number would explode and likely account for the remaining 40 ppm. Anyway, a rough calculation puts the 200 ppm number in context.

But it is an unrealistic number, because taroilsands extraction is very energy and water intensive, time consuming, and promises to remain that way. Barring some magic technology that makes cheap energy possible, in which case, we’d just use that and avoid all the mess, we won’t ever get to that number.

To summarize, 200 ppm is a reasonably accurate mathematical calculation that is wildly out of context. Sounds familiar?

The larger point is that advocates of all stripes, politicians, lobbyists, chambers of commerce, industry interest groups, corporations, and organizations pushing against them use numbers to make things sound scary and big. People who rail against government spending routinely talk about Canada’s deficit being in the billions of dollars, but when we look at it as a deficit/GDP ratio, the numbers are under control, and there’s no need to panic. In advocacy, it’s great to find a number that makes a fantastic point, somehow to bring a message home. I am sure you remember this one in the wake of the BP oil mega spill. Businesses do this all the time as well, with much greater success. I’m sure you’ve heard this trope about small businesses being the engine of job creation based on just the gross number of jobs they create. Yes, but they’re also the engine of job destruction because they go under a lot, but we don’t see that often.

As someone who has all their training as a scientist, and who does not like numeric misleading, being an activist/advocate is tricky. You work with people who are (rightly in many instances) trying to fight bad policy, and bad outcomes. The taroilsands are terrible, especially given that we’re cooking the planet and we’re deliberately spending billions of dollars investing in them. Regardless of whether they’re going to be responsible for 20 ppm, or 200 ppm, the trajectory of investing in an especially inefficient fossil fuel extraction when we should be phasing out all fossil fuel use is the big egregious wrong here. You are also trying to influence a public that finds it very hard to put numbers in context. No one will ever see a billion dollars, there’s no perceived difference between a million barrels and a trillion barrels, it’s all big numbers! So, the temptation is to use big numbers to scare people. I can understand how that happens, but I can’t bring myself to necessarily be okay with it. I will tolerate it, I guess, because the corporations, governments who produce the raw data underlying these numbers know what they mean, but distort them continuously to serve their agenda, and the media, some of whom are number literate abet this misleading. So some push back is necessary, but I will roll my eyes when it happens.

XKCD Does Metric

Xkcd metric

converting_to_metric.png (PNG Image, 740×554 pixels).

One of the nicest things about moving to a metric country is, well, the metric system! Of course, my brain now does a weird mixture of metric and non-metric for a lot of things. I have, in general, lost the ability to figure out fuel efficiency in anything other than mies per gallon, even though the inverse relationship, litres per 100 km does a much better job of actually telling you what your fuel costs are (hint, multiplication is easier than division!). But, I am getting back distance in metric, weight in metric, and best of all, volume, goodbye quarts, pints, gallons, hello litre. Finally, 0C is freezing, not 32F, makes no sense at all.

Percentage confusion redux

One day you’re blogging about it, the next day, someone publishes a journal article about percentages and the confusion people have about them.

ScienceDaily: Two Plus Two May Not Always Equal Four: Consumer Study

In the paper “When Two and Two is Not Equal to Four: Errors in Processing Multiple Percentage Changes,” Rao and Haipeng Chen, a Carlson School doctoral alum and assistant professor at the University of Miami, show that consumers treat percentages like whole numbers, and this results in systematic errors in calculation. People simply aren’t coming up with four when they add two plus two. The paper will appear in a forthcoming issue of the Journal of Consumer Research.

Well, what do you expect? It’s not easy to take 35% off 25% in your head, unless your parents and teachers made you do mental math till your head hurt (who am I kidding, I still enjoy doing math in my head and beating people with calculators, though I get worse with every passing year). Companies that sell products based on discounting of already discounted merchandise know that people will add them up in their head and overestimate the discount. It is dishonest marketing at best, and downright deceptive if you’re extremely cynical (I believe the worst of advertisers and PR).

Wow, two posts about percentages in two days, I must have nothing better to do…

Percent and Percentage Points

In a previous post today, I mentioned that breast cancer screenings had dropped 4 percentage points from 70-66%. To my eternal annoyance, most headlines I see refer to this as a 4% decline. This is wrong. The actual decline is can be mentioned as a percent decline only if you report that number directly.

\% decline=\frac{(old-new)*100}{old}

This is such basic math that I feel foolish just to point it out, but this nomenclature confusion dominates our reporting. If you assume that the number of women remained constant (In this particular case, the assumption is true because the results are from a survey of 10,000 women), then the actual percent decline would be (70-66)/70 = 5.7%, that would be, well, a lot more than 4%!

See here for wikipedia discussion.