One Cheer for Buy Local?

I’ll start by saying the “buy local” movement is deeply misguided in many ways. The belief that locally grown food is more environmentally friendly is just plain wrong for fairly obvious reasons.

I don’t want to be confused with these people who fail to do basic cost-accounting. The “buy local” crowd simply does not understand basic concepts of comparative advantage and the gains from trade. Thus only one cheer.

Where to start? When I was in high school my friends and I played some role playing games from the White Wolf universe. (Full of vampires, werewolves, and other creatures, mostly in the modern world.) White Wolf had a “support your local comic store” philosophy. As in, if you see this role-playing guidebook at a big book store in an out-of-town trip, go back home and buy it or order it from your local comic store. (Presumably this idea also applied to internet sales.)  I think this is actually a good idea.

Why? Can’t a big book store or an internet vendor carry a bigger selection and more efficiently supply us with role-playing books? Yes. Maybe. But the local comic book store is supplying something else. Maybe the store owner has deep knowledge of the products he sells. Maybe he can answer questions, even hard-to-google questions, about Dungeons and Dragons or comic books. You get access to this knowledge “for free”. Meanwhile the comic store has fixed costs: inventory, keeping the lights on, paying staff, etc. It would be a little bit rude to pump the store owner for his specialized knowledge, which he dispenses for free, then turn around and price-shop from someone who will undercut him. (The internet vendor has lower inventory costs, because they can make-to-order or keep a few copies on hand for a much larger population than what the local store serves. At some point, the local comic store can't compete with these economies of scale.)

In this sense, maybe there is a case to be made for supporting local boutique-style shops over internet vendors or big stores in the nearest big city. The higher price you pay is like paying “club dues”, and you get access to specialized knowledge for paying these dues. You might also get a sense of community. I would often run into people I knew and have nerdy conversations at my local comic shop. If you value this kind of interaction, it’s probably worth supporting your local shop.

Maybe there’s an even better model, where nerds and artisans get paid directly for their expertise, so we do away with this “marked-up retail” model of reimbursing them. Pay directly for the expertise, then shop for the best price anywhere we can find it. Or maybe there are enough online forums and discussion groups that this information is freely available or easily search-able. (Careful with this. Ever run into a question that’s hard to Google? I sure have. I alluded to this problem above.) But it’s worth thinking about whether there’s some wisdom to this “buy local” stuff.

Some Thoughts on Teaching At Work vs. College

Cross-posting from my Facebook page.

I’ve been trying to learn some data science concepts and teach them to my team at work. A few thoughts and observations.

1.  It’s different from teaching physics to engineering students (my previous experience with teaching). My team at work needs to actually learn this stuff because it affects their ability to do their jobs. The engineering students were eager to get their A (or B or perhaps C) and then forget everything. Best case scenario, they might use 10% of what they learned in their physics class. The class was mostly useless and they knew it. Motivation is important.
2.  There is a powerful and tempting illusion that your listeners understand you as well as you understand yourself. Resist this illusion. Do you remember how long it took for these concepts to sink in when *you* learned them? Nobody soaks it up in a single lecture. Be realistic about your expectations. (I was ecstatic when someone told me he understood ~30% of my discussion.) It usually takes time and repeated exposures and some effort studying the material outside of class.
3.  I have a pretty good memory (sometimes), and I have to remind myself that not everyone has this gift. (I remember explaining a chemistry lab to the valedictorian of my class in high school. Something about how the experiment we were doing was a straightforward application of a previous unit, and he’d said something like “Nobody remembers all that crap.”) When I have baffling conversations with colleagues, I remember them. I sometimes understand them *years* later, when it finally clicks, when I finally acquire the necessary context to understand. “Oh, *that’s* what that guy was talking about!” I think most people just forget about stuff they don’t understand and it’s gone for good? Maybe other people have this experience? (If this is a more common experience, that would make me more hopeful.)
4.   If you’re going to teach something, know your shit. Practice. Review the material multiple times. Know it inside and out. Rehearse explaining it to a skeptical or confused audience. In the reading group I’m leading at work, we’re reading a chapter out of a data science textbook. I’ve read it through three times now, and read some passages 10 or 20 times to get the point. The same principle applied when teaching physics. I knew some grad students who didn’t prepare adequately or at all, and their students probably resented them for it.
5.  Related to 2) and 4), there is something called the “illusion of explanatory depth”. You feel like you understand things more deeply than you do. You might read something and be nodding your head, but it might not be sinking in as well as you think. Stop yourself, summarize what you just read in plain English, pretend you are explaining it to an audience, etc. Better learn you’re confused now than while standing in front of an audience, whose respect you’re trying to hold.
6.  Watch your audience. Look at their faces and scan for signs of confusion. You may just need to slow down and reiterate a point. Or maybe you need to ask if anyone has questions. This is a difficult skill, and I’m not really sure I have it. It’s much easier to accommodate a group of five or ten motivated listeners than a room full of 30 students, though.
7.   Not everyone will “get it.” That’s okay. Be willing to write off some percent of your audience. If a few of them absorb a substantial fraction of the material, that’s a win!
8.  There is some combination of “here are practical things you need to know to use these methods” and “here are the academic/theoretical underpinnings of what we’re doing.” You can still do quite a lot if you only have the former but lack the latter. But ultimately you should be able to describe what you’re doing and answer tough questions from people who are skeptical of your analysis. You need the theoretical underpinnings to do this. Imagine someone designing a building entirely by using engineering software vs. someone who understands the physics of force diagrams and could validate some of what the software is doing by hand or from first principles. My guess is that the one with a better understanding of the physics is less likely to make a huge conceptual mistake. Just so with modern statistics.
9. I recently read Bryan Caplan’s The Case Against Education. There are long and depressing sections about how little people actually retain from their educations (high school *and* college). Also, “transfer of learning”, the application of concepts from one field to a related problem in a different field, is virtually impossible to find in the real world. (As in, studies of this topic fail to find it, despite heroic efforts to search for it.) Not to be too cynical here, but try to temper your enthusiasm with a little skepticism.
10.  Teaching a physical skill is somewhat easier in the following sense. You can witness someone trying and failing, critique their form, and have them try again. It’s harder to observe understanding, because that takes place inside someone’s head. (Getting people to speak up when they’re confused is difficult, as any teacher will tell you.) Also, people doing physical activities are usually more motivated and are explicitly “opting in.” I’m thinking mostly of the various martial arts I’ve done. Particularly jiujitsu, where you often have to use a technique against an unwilling opponent who is trying to stop you.