[Mediation-information] Sensitivity analysis for a GAM

[Kosuke Imai]

Hi Louise,

  Thanks for your email.  Unfortunately, our software, mediation, does not have sensitivity analysis for GAM.  We hope to expand the capability of the software in the future, though.  However, you should still be able to use GAM to calculate mediation effects. 

Best,
Kosuke

Department of Politics
Princeton University
http://imai.princeton.edu


On Dec 10, 2011, at 11:54 AM, Glew, Louise wrote:

> Dr. Imai,
>  
> I’m working on a series of quasi-experimental assessments of the impact of biodiversity conservation interventions. I was wondering if I could ask your advice on how best to conduct a sensitivity analysis on a generalized additive mixed model.
>  
> I’m analyzing a time-series of remotely-sensed imagery, to explore the impact of a series of conservation interventions against matched controls in northern Kenya. The properties of the data have precluded using a GLMM,  and are particularly challenging as they are both spatially auto-correlated and serially-dependent.
>  
> When working with less complex data, I have used the ‘rbounds’ and the ‘mediation’ package to compute Rosenbaum’s sensitivity bounds. Reading the documentation for the mediation package, it became apparent that the current function can only handle linear models. The GAMM I’ve fit to the data is technically a penalized linear model, but the errors are not normally distributed (due to the spatial and temporal correlation). I was wondering if you could advise me of any alternative sensitivity analysis methods which may be able to cope with non-linear data please?
>  
> Thank you,
>  
> Best wishes,
>  
> Louise
>  
> Louise Glew (MEnvSci)
> Monitoring and Evaluation Specialist
> Conservation Science Program
> World Wildlife Fund
> 1250 24th Street, NW
> Washington, DC 20037-1193
> Office: 202-495-4184
> Skype: louise.glew
> Louise.Glew at wwfus.org
> worldwildlife.org
>  
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