· A remarkable sounding experiment – randomizing the freedom to short-sell stocks  – is covered on Bloomberg. They worked with a money manager and randomized which stocks they changed the supply of lendable shares in, working with over $580 million in securities. Bottom line seems to be that positive and negative shocks on short-selling supply had no impacts on prices or volatility. Finance friends, tell us what you think (the paper is here ).
· The Obama campaign’s advertising experiments are covered in Slate . Interesting to read how they move beyond average impacts of treatments to micro-targeting….”The Obama campaign’s long reach and big budget should significantly expand the frontiers of experimental politics, which have been limited by a tax code that prevents academic and nonprofit researchers from disseminating partisan messages.”
· Moving beyond WEIRD samples to “Mechanical Turks”? The Economist  discusses the use of people who have signed up for Amazon’s mechanical Turk service as an alternative to using American undergrads in lab experiments. I’m not sure how much an improvement in representativeness this is. For development economists, there may be more interest in the new Busara Center for behavioral economics launched in Kenya, which recruits lab participants from Kiberia slums (see the IPA blog  for more).
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