Ana, I have read quite a few papers that employ PCA but I have never seen them refer to the specific loadings values; however, I am primarily reading in the field chemoinformatics and this may vary in ecological studies (which I assume this would be given the list). Generally a loadings plot is generated alongside the scoresplot. PC loadings are correlation coefficients between the PC scores and the original variables. Therefore most people simply look for variables clustered in similar areas of the loadings plot as sample clusters in the scores plot and refer to these variables with no mention of the specific values. Depending upon you particular field this approach may be different but this has been my experience wherever I have seen PCA applied.
Hope this helps, Regards, Charles Determan On Tue, Apr 1, 2014 at 10:03 AM, Ana Serronha <[email protected]> wrote: > Hi everyone, > > I have read that, loadings (from pca) more than .5 are typically > considered strong; loadings between .3 and .5 are acceptable; and loadings > less than .3 are typically considered weak, am I correct? > However, I can't find a credible reference to use. Can you suggest me a > book or a paper to use as a reference? > Thanks > > > > > -- > Ana Marta Serronha > > CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos > Campus Agrário de Vairão > Rua Padre Armando Quintas - Crasto > 4485-661 Vairão > Portugal > > Tel. +351 252660428 ou +351 252660411 > Fax: +351 252661780 > > [[alternative HTML version deleted]] > > > _______________________________________________ > R-sig-ecology mailing list > [email protected] > https://stat.ethz.ch/mailman/listinfo/r-sig-ecology > > -- Charles Determan Integrated Biosciences PhD Candidate University of Minnesota [[alternative HTML version deleted]]
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