Almost random


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Randomized program implementation is currently seen as the ‘gold standard’ for impact evaluation in the search for the most effective development interventions. Earlier studies were criticized for their limited scope, so some of these interventions now involve large populations. Unfortunately, the larger the intervention, the larger is the danger that people who were supposed to get the treatment do not receive the intervention and vice-versa. Do such deviations invalidate the conclusions drawn from randomized studies? My colleague Harold Alderman together with Harvard economist Sebastian Linnemayr address this question in a paper  that evaluates the impact of a randomized nutrition intervention on the anthropometric status of Senegalese children. The paper confirms that the measured impact is stronger in villages that actually received the intervention compared to those that should have received it. This confirms the view that large scale community based health promotion can get parents to take better care of their children—and that children will benefit from this. The paper illustrates that randomization, even though it was not strictly followed, still assists in identifying the program’s impact.   Given the rapidly increasing number of large-scale randomized interventions, more studies addressing this sort of questions are needed. The most valuable lessons will come from studies that confront these difficulties rather than ignoring them. The real world differs fundamentally from the laboratory setting in which the method of randomized experiments first was developed. It is time to address this fact in order to learn real lessons from and for real people.



Shanta Devarajan

Senior Director, DEC and Acting World Bank Group Chief Economist

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February 10, 2009

This economic crisis clearly show how artificial is the economic situation of those so call developed country.
In Africa more than 90% of people buy their house cash, more than 90% of people buy their car cash. No credit cart given unless you pay in advance.
If no credit means economic crisis then we should not be surprised why Africa is always in crisis.
Can we imagine all these big companies like GM are unable to survive without credit for only one month?
America, Europe Economic situation collapse because no credit, so I wonder how Africa manage to survive without credit. We African should be proud of our economy as stronger than those so called developed country.
African can afford to have nice house nice car if they are offered as American, European... no down payment credit to get a house and a car.
I remember saving 4 years before buying my first car or saving years to be able to build a house.
American and European don’t need to save, they just need to walk into the bank and get a mortgage for 30 years, how lucky they are?