A black mark or bar for each death is placed in the

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Unformatted text preview: 854. A black mark or bar for each death is placed in the situation of the house in which the fatal attack took place. The Pump Today in London – a Memorial to John Snow A Natural Experiment In the …rst, there is a ‘ shock’which is water polluted with cholera and this hits a treatment group – those who take water from the Broad Street Pump, but not a control group – brewers and people in the workhouse. The treatment and control group are comparable – breath the same air. Crucially, assignment to the treatment and control is ‘ if’random – as it is not determined by any characteristic which would in‡uence your ability to withstand cholera. James A. Robinson (Harvard) The Emergence of Modern Economic Growth: A Comparative and9, 2009 September Historical Analysis 12 / 24 Experiments and Instrumental Variables Broad Street is as close to real situation mimicking an actual experiment as you can get. But what you really need is an exogenous source of variation in the variable whose causal impact you want to examine. An experiment is the cleanest example of such exogenous variation, but more generally what we need is an instrument or an instrumental variable. Let’ look at some more examples, some of which are like real s experiments. James A. Robinson (Harvard) The Emergence of Modern Economic Growth: A Comparative and9, 2009 September Historical Analysis 13 / 24 The Korean Experiment Korea: economically, culturally and ethnically homogeneous at the end of WWII. If anything, the North more industrialized. “Exogenous” separation of North and South, with radically di¤erent political and economic institutions. Exogenous in the sense that institutional outcomes not related to the economic, cultural or geographic conditions in North and South. Approximating an experiment where similar subjects are “treated” di¤erently. Big di¤erences in economic and political institutions. Communism (planned economy) in the North. Capitalism, albeit with government interventi...
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This document was uploaded on 02/28/2014 for the course ECON 2328 at Harvard.

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