What is it?
A package for the R language which generates step plots, influence plots, coefficient-distribution-influence (CDI) plots, and influence metrics for linear models as described in the paper [Bentley, N., Kendrick, T. H., Starr, P. J., & Breen, P. A. (2011). Influence plots and metrics: tools for better understanding fisheries catch-per-unit-effort standardisations. ICES Journal of Marine Science, 69: 84-88. doi:10.1093/icesjms/fsr174](http://icesjms.oxfordjournals.org/cgi/reprint/fsr174? ijkey=zZGx3RoK1zkxhaL&keytype=ref) (There is a pre-print, pre-review version here but the above link is recommended as it gives full access to the final version)
How do I get it?
The package is still in development. A beta version is available under Releases.
Eventually influ will be submitted to the Comprehensive R Archive Network for direct installation via the
install.packages R function.
How do I use it?
We recommend looking at the
influ vignette first. But if you don't have time for even that, here's an even quicker run down....
#Install the package after downloading it install.packages("/path/to/influ_0.X.zip",repos=NULL) #Windows install.packages("/path/to/influ_0.X.tar.gz",repos=NULL) #Linux #Load the package library(influ) #Fit a glm model (the first term, in this case year, should be a factor!) myModel = glm(log(catch)~year+effort+month+area+depth+method,data=myData) ##Create an influence object for that model myInfl = Influence$new(myModel) myInfl$calc() ##Look at the summary data.frame and execute the various methods ## to create plots myInfl$summary myInfl$stanPlot() myInfl$stepPlot() myInfl$influPlot() myInfl$cdiPlot('month') myInfl$cdiPlotAll()