Sunday, March 15, 2009

Terry Pratchett: Going Postal

Terry Pratchett's's Going Postal is another in Pratchett's Discworld series. I've only read a handful of these stories, but they've all been fun, lightweight fantasies that explore greater and lesser societal issues in a skew universe.

In this story, Pratchett looks at competition in business and the effect of the competent entrepreneur. Okay, you'd be unlikely to see it that way if you read the book, but those are the themes that I extracted from the story. Lord Vetinari wants to rejuvenate the Ankh-Morpork postal service, and he needs a motivated, creative manager to manage it. He plucks Moist von Lipwig from the scaffold and makes him an offer he can't refuse. Moist turns out to be very creative; his history as a schemer and con artist having prepared him to read people on the spot and make up convincing stories which he can fill in the details of later when he figures out which direction he's going to take the scam.

In this case, Moist is going up against the corrupt monopoly that runs a private semaphore-based messaging system that is closer to a telegraph than a message carrier. The Grand Trunk also has labor relations problems, since their lack of attention to maintenance issues has led to a surfeit of injuries and deaths among the employees. Moist is able to out-compete the Grand Trunk in order to regain the customer base the official post office lost long ago and use an occasional bit of sabotage to reduce the Grand Trunk's ability to stay in the game.

In the end, Moist resurrects the post office by acting as the nimble entrepreneur (with a side of underhandedness) in competition with an entrenched bureaucracy. He has enough obstacles (decades of undelivered mail piled up in the post office, attacks by the competition) and humanity (pursuing a surprising love interest) to be a sympathetic character. Pratchett turns the competitive environment on its head, but I think most readers will see that it's normally government monopolies that are resistant to change, and the story shows that it's the stodginess and resistance to change that lead to poor service. If the competitors have the ability to try new things (normally, not including violence and sabotage), the customers come out ahead, and competition improves all of the enterprises touched by it.

Thursday, March 12, 2009

Julia Robinson Mathematics Festival: March 29 and May 2

If you're interested in math, puzzles, and encouraging middle and high school students to learn more about math, I recommend taking some time to help out at the Julia Robinson Mathematics Festival on March 29th in Emeryville. I heard about the festival at a talk last year. I actually helped out as a puzzle mentor for the geeky (adult) audience of this talk, and had a great time talking people through one of the puzzle sets.

The JRMF presents great puzzles--graduated challenges, interesting applications--in a context that encourages kids to work together on solving them. This both encourages the ones who don't get the solution right away and cements the mastery of those who caught on more quickly. Everyone has fun, and many youngsters are exposed to the notion that math is relevant and applies in many everyday situations.

They currently have an event scheduled at Pixar in Emeryville on Sunday March 29, and are planning another for May 2, but don't have a firm location for the latter yet. They're looking for adult volunteers to staff math tables. Here's the announcement I got via email.

General information:
The Julia Robinson Math Festival
The festival, for students in grades 6-12, will consist of morning mathematical activities lunch, an accessible (to middle school and high school students) math talk, and, of course, prizes. Julia Robinson is the Berkeley mathematician who, among other important discoveries, made significant contributions to the solution of Hilbert's Tenth Problem. Here's a bit of biography, and a bit about Hilbert Tenth.

The morning activities will cover a wide variety of mathematical topics, including abstract problem-solving techniques like symmetry and parity as well as content ranging from arithmetic and algebra through combinatorics and topology. Students will have time to visit at least five or six activities during the morning session. For a sample activity, see the Candy Conundrum (and Teacher's Guide). (There are downloadable links at Each activity table will be staffed by an expert, and upon reaching certain milestones in their understanding of the mathematics behind the puzzle or game or activity, students will be rewarded with raffle tickets for the afternoon's prize drawings. Thanks to our sponsors, the desJardins/Blachman fund and Pixar, we have an impressive array of prizes!

For those who want to staff a math table:We need people who are comfortable with hard math problems, and who can patiently work with kids to guide them toward progress. We are looking for guides who will listen to what kids have worked on, ask some (perhaps leading) questions, and then let the kids continue to progress. If you're interested, contact Joshua Zucker (email: first.last at stanfordalumni dot org), and if you're not sure you're interested, contact him anyway and he can give more detailed information about the expectations of the table leaders.

Monday, March 09, 2009

Harry Turtledove, Opening Atlantis

Harry Turtledove's Opening Atlantis is a candidate for the Prometheus Award. I suspect it'll be chosen as a finalist since it's well written and interesting and has strong pro-freedom themes. Unfortunately for Turtledove (who was a co-winner last year for The Gladiator), some of my other favorites have more topical themes and are just as fun to read.

Opening Atlantis posits that an extra contintent has been inserted in the middle of the Atlantic, but otherwise history and geography are pretty much unchanged compared to our timeline. Not surprisingly, the new continent is noticed during the Age of Discovery, and since it's located in the Atlantic, it is named for the (realized to be mythological) Atlantis. The geography, flora, and fauna are surprising to the discoverers and eventual settlers. One recurring side note is the characters who recognize that the indigenous species are different in the old world, on Atlantis, and in Terranova (North America). They don't quite point to the possibility of evolution explicitly, but it's the kind of idle wonder that one imagines occurs many times before an explanation is found.

Turtledove's story is presented in three parts from successive eras, which are roughly Settlement and Independence, Battling the Pirates, and Dragged into the European War. Each of the segments has Edward Radcliffe or his descendants as central figures, and the first and last each features a different battle over freedom-related issues. In the first part, Atlantis is discovered and settled by English, French, and Spanish fishermen and their families. Lured by familiar climate, each group settles on a different section of the coast, and builds multiple towns that trade, but maintain separate cultures. The conflict in Part one comes when a nobleman sent away by the British Crown decides that British Atlantis is his new fiefdom. Since the settlers intentionally migrated in order to get away from kings and lords and their incessant war and taxation, it isn't long before they rise up and defeat the invaders. They are helped a lot by their familiarity with local conditions, and their willingness to fight as insurgents.

In the second part, two of Edward's descendants, Red Rodney Radcliffe (a pirate captain) and William Radcliff (a shipping magnate) battle over the fate of a pirate stronghold on the western edge of Atlantis. William allies with other major shipping owners to defeat the pirates and ensure that they'll be able to trade freely. I could say that the freedom-related themes have to do with free trade and cooperation among private enterprises to address a common problem, but truthfully this is just a setup for a series of naval battles. The good guys win.

The third part (my nickname was "Dragged into the European War") covers a period of strife between Britain and France. Early on, there was some discussion of which side Spain would take, and there are hints that other powers are engaged in other theaters, but we only see the battles that take place in Atlantis. Victor Radcliff leads the British-allied settlers, and his French-settler counterpart Roland Kersauzon is descended from the frenchman who first identified the new continent. Early on, the French settlers are reinforced by French troops, but for most of this war, the British navy controls the oceans but isn't concerned about the fate of Atlantis, so the armies on the ground are on their own. Tactics rule the day, and the settlers teach the regular armies several lessons about dealing with insurgents and familiarity with local terrain.

Victor Radcliff is joined by Blaise, an escaped slave who becomes a leader among the British irregulars. A lot of the conflict in this section is about how competent Blaise is and how he is able to win over British settlers who haven't had much previous contact with Blacks. The French and Spanish they run into (and the British regulars) are much less tolerant. Blaise finds several opportunities to point out the parallels between his situation and the freedom that the other settlers are fighting for.

Overall, it's quite a fun read and well up to Turtledove's normal high standards. The characters and their battles and strategic surprises are well-drawn and plausible.

Monday, March 02, 2009

Stephen Ziliak and Deirdre McCloskey: The Cult of Statistical Significance

Stephen Ziliak and Deirdre McCloskey's The Cult of Statistical Significance is a poorly argued rant about what appears to be an important topic on the pursuit of scientific knowledge. Ziliak and McCloskey argue that many of the statistical sciences have been using the wrong metric to determine whether the results of experiments are interesting and relevant. They report on a few detailed reviews of articles in top journals in economics, psychology, and other fields to show that the problem they describe is real and pervasive. Unfortunately, they are much more interested in casting aspersions on the work and influence of Ronald Fisher and building up his colleague William Gosset, and so they don't actually explain how to apply their preferred approach. In amongst the rant, they do manage to make the defects of Fisher's approach clear, though it's tedious reading.

The basic story is that Fisher argued that the main point of science is establishing what we know, and to that end, the important result of any scientific experiment is a clear statement of whether the results are statistically significant. According to Fisher, that tells you what confidence you should have that the results would be repeated if you ran the experiment again. Ziliak and McCloskey want you to understand that a result can be statistically significant but practically useless. And there are worse cases, where statistical significance and Fisher's approach leads scientists to hide more relevant results, or worse to conclude that a proposal was ineffective when the data show that a large effect might be present, but the experiment failed to show that it was certain. Ziliak and McCloskey want scientists to primarily report the size of the effects they find, and their confidence in the result. To Ziliak and McCloskey, a large effect discovered in noisy data is far more important than a small effect in very clear data. They point out that with a large enough sample, every effect will be statistically significant. (Though they don't explain this point in any detail, nor give any numbers on what "large enough" means. I have an intuitive feeling for why this might be true, but this was just one of many points that wasn't presented clearly.)

They describe a few stories in detail to show the consequences for public policy. Vioxx was approved, they claim, because the tests of statistical significance allowed the scientists to fudge their results sufficiently to hide the deleterious effects. (It's not clear why this should be blamed on statistical significance rather than corruption.) They also present a case that a study of unemployment insurance in Illinois found a large effect ($4.29 in benefit for every dollar spent), but gave the Fisherian conclusion, not just that the result wasn't statistically significant, but that there was no effect. It turned out that a careful review of the data showed that the program had a statistically significant benefit-cost ratio of $7.07 for white women, but the overall benefit-cost ratio was not statistically significant because the $4.29 was only statistically significant at the .12 level, while under .05 or less is required by Fisher's followers.

Ziliak and McCloskey demonstrate that they're on the right side of the epistemological debate by supporting the use of Bayes' Law in describing scientific results, but beyond one example, they don't explain how a scientific paper should use it in presenting results. The use of Fisher's approach gives a clear guide: describe some hypotheses, perform some tests, finally analyze the results to show which relationships are significant. With Bayes, the reasoning, approach and explanation are more complicated; but Ziliak and McCloskey don't tell how to do it. Of the 29 references to Bayesian Theory in the index, 24 of them have descriptions like "Feynman advocates ...", or "Orthodox Fisherians oppose ...". There aren't any examples of how one might write a conclusion to a paper and show Bayesian reasoning, even though they pervasively give examples of analogous Fisherian reasoning that they find unacceptable.

Another significance question that Ziliak and McCloskey argue is important (but that they don't explain adequately) and that statistical significance hides is how much various treatments or alternate policy approaches might cost. Fisher's approach allows authors to publish that some proposal would have a statistically significant effect on a societal problem or the course of a disease and not mention that the cost is exorbitant and the effect small (though likely). Ziliak and McCloskey argue that journal editors should require authors to publish the magnitude of any effects and a comparison of costs and benefits. According to the reviews they've done and others they cite, it's common in top journals to omit this level of detail and to focus on whether experimental results are significantly different from zero.

Another of the authors' pet peeves is "testing for difference from zero". They claim that it's common for papers to report results as "statistically different from zero", when they're barely so. They use the epithet "sign testing" for this case. The lack of attention to the size of an effect that significance testing allows means that papers get published showing that some effects have a positive effect on a problem, even when the effect is barely different from a placebo. And there are enough scientists performing enough experiments today that many treatments with no real effect will reach this level of significance purely by chance.

Overall, the book spends far too much time on personalities and politics. Even when the discussion is substantive, too much effort goes into why the standard approach is mistaken and far too little on how to do science right, or why their preferred approaches would actually lead to better science.

For the layperson trying to follow the progress of science, and occasionally to dip into the literature to make a decision about what treatment to recommend to a family member or what supplements would best enhance longevity or health, the point is that scientific papers have to be read more carefully. Ziliak and McCloskey argue that editors, even of prestigious journals, are using the wrong metrics in choosing what papers to accept, and often pressure authors to present their results in formats that aren't useful for this purpose.

When reading papers, concentrate on the size and the costs of the effects being described. Significance can be relevant, but the fact that a paper appeared in a major publication doesn't mean that the effects being described are important or useful. Don't be surprised if the most-cited papers in some area don't actually present the circumstances in which an intervention would be useful. Don't assume that all "significant" effects are relevant or strong.