Cristian, have a look at http://j.mp/CEMweights which explains the CEM weights. Like Stefano, I don't think it would make sense to run an analysis without the weights.
Gary--Gary King - Albert J. Weatherhead III University Professor - Director, IQSS - Harvard University
On Fri, Mar 16, 2018 at 11:59 AM, Cristian Vaccari <C.Vaccari@lboro.ac.uk> wrote:
Dear all,
I am using CEM in a paper based on survey data. The goal is to estimate the relationship between exposure to political incivility on social media and an index of political participation (a count of eight different activities). After matching units based on a set of covariates, I run a negative binomial regression using the weight calculated by CEM that equalizes the number of treated and control units within each stratum.
Among the feedback I have received on this paper has been the suggestion that I should run the analysis on the CEM-matched units, but without using the CEM-generated weight.
I have tried running the analysis only on the matched units without using the weight and the results are consistent with the analysis where I used the weight, but it seems to me using the weights would be more appropriate. Would anyone be able to comment on whether using the matched units but not the weight is a sensible/acceptable idea or not?
Many thanks for your help and for developing this great tool!
Cristian