Dear all,
Please join us for the Applied Statistics Workshop (Gov 3009) this
Wednesday, February 20 from 12.00 - 1.30 pm in CGIS Knafel Room 354. Fernando
Martel Garcia <http://www.iq.harvard.edu/people/fernando-martel-garcia>, a
Research Fellow at the Harvard School of Public Health, will give a
presentation entitled "When and Why is Attrition a Problem in Randomized
Controlled Experiments and How to Diagnose It". As always, a light lunch
will be provided.
Abstract:
Attrition is the Achilles' Heel of the randomized
experiment: it is fairly
common, and it can unravel the benefits of randomization. This study
considers when and why attrition is a problem, and how it can be diagnosed.
The extant literature remains ambiguous because it relies on the language
of probability, whereas problematic attrition depends on the underlying
causal relations. This ambiguity arises because causation implies
correlation but not vice versa. Using the structural causal language of
directed acyclic graphs I show attrition is a problem when it is an active
collider between the treatment and the outcome, or when the latent outcome
is a mediator between the treatment and the attrition. Moreover, whether
observed outcomes are representative of all outcomes, or only comparable
across experimental arms, depends on two d-separation conditions. One of
these is directly testable from the data.
An up-to-date schedule for the workshop is available at
http://events.iq.harvard.edu/events/node/1208.
Best,
Konstantin
--
Konstantin Kashin
Ph.D. Candidate in Government
Harvard University
Mobile: 978-844-0538
E-mail: kkashin(a)fas.harvard.edu
Site:
http://www.konstantinkashin.com/<http://people.fas.harvard.edu/%7Ekkashi…