Dear Applied Statistics Community,
Please join us on Wednesday October 1st when Gary King, the David Florence
Professor of Government, will present "Matching for Causal Inference Without
Balance Checking". A draft of the paper is available here:
http://gking.harvard.edu/files/cem.pdf , and here is the abstract:
We address a major discrepancy in matching methods for causal inference in
observational data. Since these data are typically plentiful, the goal of
matching is to reduce bias and only secondarily to keep variance low.
However, most matching methods seem designed for the opposite problem,
guaranteeing sample size ex ante but limiting bias by controlling for
covariates through reductions in the imbalance between treated and control
groups only ex post and only sometimes. (The resulting practical difficulty
may explain why many published applications do not check whether
imbalance was reduced and so may not even be decreasing bias.) We introduce
a new class of "Monotonic Imbalance Bounding" (MIB) matching methods that
enables one to choose a fixed level of maximum imbalance, or to reduce
maximum imbalance for one variable without changing it for the others. We
then discuss a specific MIB method called "Coarsened Exact Matching" (CEM)
which, unlike most existing approaches, also explicitly bounds through ex
ante user choice both the degree of model dependence and the causal effect
estimation error, eliminates the need for a separate procedure to restrict
data to common support, meets the congruence principle, is approximately
invariant to measurement error, works well with modern methods of imputation
for missing data, is computationally efficient even with massive data sets,
and is easy to understand and use. This method can improve causal inferences
in a wide range of applications, and may be preferred for simplicity of use
even when it is possible to design superior methods for particular problems.
We also make available open source software which implements all our
suggestions.
The applied statistics workshop meets in room K-354, CGIS–Knafel (1737
Cambridge St) at 12 noon, with a light-lunch served. The presentation will
begin at 1215 and the workshop usually ends around 130. All are welcome to
attend,
Cheers
Justin Grimmer
Dear Applied Statistics Community,
Please join us tomorrow (Wednesday, 9/24) when we welcome Ben Fry to the
applied statistics workshop. Ben's research explores data
visualization—more details can be found here (http://benfry.com) --
including details of his recently completed book "Data Visualization" and
samples from his previous work (http://benfry.com/projects/).
The workshop will meet at 12 noon in room K-354, CGIS-Knafel (1737 Cambridge
St) with a light lunch served. The presentation will begin at 1215 and
usually ends around 130 pm. All are welcome—
Cheers,
Justin Grimmer
Dear Applied Statistics Community,
Welcome back for the 2008-2009 academic year. We have an exciting lineup
of speakers this coming semester. The workshop kicks off this coming
Wednesday, September 17th, with Andrew Gelman, Department of Statistics and
Political Science, Columbia University. Andrew will be presenting results
from his recently released book "Red State, Blue State, Rich State, Poor
State". Here is an introduction to the book from the publisher:
With wit and prodigious number crunching, Andrew Gelman and his coauthors
get to the bottom of why Democrats win elections in wealthy states while
Republicans get the votes of richer voters, how the two parties have become
ideologically polarized, and other issues. Gelman uses eye-opening,
easy-to-read graphics to unravel the mystifying patterns of recent voting,
and in doing so paints a vivid portrait of the regional differences that
drive American politics. He demonstrates in the plainest possible terms how
the real culture war is being waged among affluent Democrats and
Republicans, not between the haves and have-nots; how religion matters for
higher-income voters; how the rich-poor divide is greater in red not blue
states--and much more.
With the excitement surrounding the current presidential races, this
presentation promises to be informative to anyone interested in separating
the facts from the myths about vote choice in America. For those
interested, a blog is available about the book <http://redbluerichpoor.com/> ,
which is also available for
purchase<http://www.amazon.com/gp/product/069113927X?ie=UTF8&tag=restblstristp-20&li…>
.
As a reminder, the applied statistics workshop meets every Wednesday in
CGIS-Knafel, 1737 Cambridge St, room K-354 (Previously N-354, before the
Chad Johnson/Prince-esque name change that recently swept through the north
building). We start at 12 noon with a light lunch and the presentations
usually begin around 1215.
To give Andrew the maximum amount of time, we will skip the normal
"business" meeting that usually starts the year. If anyone has any
suggestions about how the workshop could improve, or would like to present
at the workshop this year, please let me know (email would probably be the
quickest and most effective method)
Cheers
Justin Grimmer