Questions tagged [concurvity]
Concurvity refers to the nonlinear dependencies among covariates in an additive model, and is related to the concept of collinearity among predictors in a linear model. This tag should be used when a question is related to (multi)collinearity in the predictors of a model where the model contains smooth functions of covariates such as generalized additive models.
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Dealing with high concurvity and variable selection in GAMMs with imbalanced data (mgcv::bam)
I am using GAMMs to model the probability of occurrence of a species, applying logistic regressions with mgcv::bam() to presence-pseudoabsence data. The dataset ...
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GAMM with a global smooth term and site-specific deviations with concurvity present (mgcv::gam())
I’m fitting generalized additive mixed models in R (mgcv::gam()) to study how productivity changes over time across multiple Locations.
Each Location has repeated measurements from several plots. I ...
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GAMMs in R: How to interpret global term when concurvity with group-level smoother is present?
I've fixed my model and incorporated all the terms I believe have an effect on my response (abundance of a single species), but I'm stuck on how to interpret the long-term trend plot, ...
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High Concurvity in Random Effects of a GAMM
I'm using a Generalized Additive Mixed Model (GAMM) in R with the mgcv package. My dataset consists of multiple permanent sites sampled across multiple years, with 3 replicates at each site.
The ...
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Concurvity involving categorical variables (?)
I recently learned how to test for concurvity on a GAMM I constructed, but I'm confused about how to test if 2 factors (2 categorical parametric terms), or 1 factor and a smooth term, are too closely ...
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How to deal with collinearity or concurvity between fixed effect variables and random effect variables?
My current work involves asking subjects from different groups to pronounce multiple words, and I am interested in understanding the relationship between word duration and groups.
In R syntax, this ...
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Concurvity and GAMMs in R
I'm having trouble understanding how to read/interpret the concurvity function output and exactly what to do about high values. My understanding of concurvity is it's the GAM equivalent to ...
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High concurvity/ collinearity between time and temperature in GAM predicting deaths but low ACF. Does this matter?
I have problems with concurvity in my thesis research, and don't have access to a statistician who works with time series, GAMs or R. I'd be very grateful for any (partial) answer, however short. I'll ...
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assessing impact of concurvity in GAM using time series of weather and mortality data
I have some questions about concurvity in a GAM using time series weather and mortality data (for details and model output see below). I'd be really appreciative of some help as most questions about ...
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How to interpret concurvity and wiggliness induced by low or high K knots in GAM models
Two questions: 1. Concurvity for factors =1, is this normal? 2. How do you interpret a partial effect when the effect is linear and lines for confidence intervals are pinched at 0?
Is it okay for ...
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High concurvity with random effect terms in generalized additive mixed effects models GAMM
I have a quick question concerning concurvity in a generalized additive mixed effects model. There are wonderful aids for identifying concurvity for GAMs not containing random effects. However, I have ...
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GAM: Do shrinkage smooth splines also address for concurvity?
I have a gam model with automatic predictor selection based on cubic splines (bs = cr) and SELECT == T or shrinkage cubic splines (bs = cs) and SELECT == F.
Now I'm wondering if predictors affected ...
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Is it okay to ignore concurvity on our GAM model?
I'm trying to model a relationship between marine debris concentration (item/m^2) with several covariates using GAM with MGCV R package. I found that the concurvity values at worst-case scenario are ...
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GAM concurvity measures greater than 1
I am currently using a gam modelling approach to describe the effects of several variables (es_sum, nat_sum, sect_sum, and prop_spec) on another variable (btwn). Each of es_sum, nat_sum, sect_sum, and ...
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Variance components of a penalized spatial GAM have very large confidence intervals
I am working through a spatial GAM example in one of Simon Wood's lectures (found here), and ran into some problems surrounding concurvity and penalization. I've read a number of other posts on ...
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