You also get entered into a drawing for $50 Amazon gift certificates based on activity (not based on performance - they're don't want to touch gambling regulations). I have gotten 2 this twice now with pretty low activity, which is nice.

The current and previous questions were focused on geo-political predictions which proved to be a surprisingly interesting to someone who doesn't really follow the news to closely. It provides a nice alternative way of learning about the world other than headlines - each question is a mini research project to quickly learn about the developments of North Korea's multistage rocket program or the likelihood of US increasing certain sanctions.

Thanks for the shout! We're excited to move into Science & Tech which lets us be much more open about recruiting and sourcing. I really hope we get lots of people from LW.

As noted in my reply below, please use the new registration site (it has an atom logo, not a dagger). That will put you in the queue to be notified when we bring up the new site. The old site will go dark this Saturday, though we will still have occasional updates on the blog. The new site will be in testing over the summer (there is an email link if you're interested) and go live in the autumn.

I couldn't believe the registration "questions".

• "A bat and a ball cost $1.10 in total. The bat costs $1.00 more than the ball. How much does the ball cost?"
• "If it takes 5 machines 5 minutes to make 5 widgets, how long would it take 100 machines to make 100 widgets?"
• "In a lake, there is a patch of lily pads. Every day, the patch doubles in size. If it takes 48 days for the patch to cover the entire lake, how long would it take for the patch to cover half the lake?"

These are the exact questions from this blog post, to the letter (and are also all very well known outside that, but sometimes in different orders). What?

Then there were a few that state "Discontinued", including one with the answers (this was multiple choice), "Completely a Fox", "In between a Fox and a Hedgehog", and "Completely a Hedgehog" (with a few others in between). Why these questions were not just removed from the form is beyond me. I'm also really interested in how, at least for a while, they may have assumed readers knew about this dichotomy, especially readers who they assumed did not know the 3 most popular analysis/rationality questions on the internet.

The main site seems to be written in Ember or Backbone.js or something, and yet it's really tough to use and is very buggy in chrome. (Closer inspection shows they may have done it without a MVC js framework. Also, they haven't minified their main JS files for some reason.)

The existing platform has all the markings of a big bureaucratic project combined with recent web and prediction market trends. Bizarre.

Regarding superfluous division by P(A): it is omitted in some applications of Bayesian reasoning.

Search theory begins with a probability map and updates the map based on searching and not finding. The calculations are done unnormalized both for speed and to preserve information. If the map started with 10,000 points distributed over all the regions in the search area, it is useful to know that searching has reduced the total to 1,000. It suggests you have exhausted the area and should reconsider your hypothesis that the subject/object/target is in this area.

There are equivalent approaches using normalization, such as including "Rest of World" as an area. But unnormalized is faster.

Thanks for the vote of confidence. I should say that while I think my paper presents things well, I cannot take credit for the statistics or experimental design. Tim van Gelder already had the machinery in place to measure pre-post gains, and had done so for several semesters. The results were published in Donohue et al. 2002. The difference here was that I took over teaching, and we continued the pre-post tests.

Although argument maps are usually used to map existing natural language arguments, one could start with the map. I like to think that the more people use these maps, the more their thinking naturally follows such a structure. I'm sure I could use more practice myself.

Just a note on terminology: the tree does have two kinds of nodes, but by virtue of being a tree, it is not a <a href="http://en.wikipedia.org/wiki/Bipartite_graph">bipartite graph</a>.

I think arguments in argument maps can be made probabilistic and converted to Bayesian networks. But as it is, it takes long enough just to make an argument map. I've recently discovered <a href="http://lac.gmu.edu/">Gheorghe Tecuci's work.</a> He's just down the hall from me, but I didn't know his work until I heard him give a talk recently. He has an elaborate system that helps analysts create structures very much like argument maps by filling in schemas, and then reasons quantitatively with them. The tree structure and the simplicity of the combination rules (min, max, average, etc.) are more limited than a full Bayesian network, but it seems to be a very nice extension of argument maps.

Oddly enough, Twardy's research in philosophy (as opposed to philosophy education) is related to Pearlean counterfactuals. He worked somewhat with Lucas Hope on a tool called "Causal Reckoner".

See:

http://portal.acm.org/citation.cfm?id=1082172&dl=GUIDE&coll=GUIDE&CFID=49488126&CFTOKEN=18921351

And:

http://www.springerlink.com/content/30m8ac6uafkxu9k3/

However, my google-fu is not strong enough to find the software itself. Possibly contacting the various individuals involved would be necessary.