Does GAM (Generalized Additive Model) have collinearity problem?












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$begingroup$


There is collinearity effect in linear regression methods. For example, this question is about collinear predictors in GLM.
But GAMs are nonlinear, do we need to check the collinearity of independent variables before using GAMs?










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    2












    $begingroup$


    There is collinearity effect in linear regression methods. For example, this question is about collinear predictors in GLM.
    But GAMs are nonlinear, do we need to check the collinearity of independent variables before using GAMs?










    share|cite|improve this question









    $endgroup$















      2












      2








      2





      $begingroup$


      There is collinearity effect in linear regression methods. For example, this question is about collinear predictors in GLM.
      But GAMs are nonlinear, do we need to check the collinearity of independent variables before using GAMs?










      share|cite|improve this question









      $endgroup$




      There is collinearity effect in linear regression methods. For example, this question is about collinear predictors in GLM.
      But GAMs are nonlinear, do we need to check the collinearity of independent variables before using GAMs?







      generalized-linear-model gam






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          $begingroup$

          GAM models can be afflicted by concurvity (the extension of GLM collinearity to GAM models).



          According to https://stat.ethz.ch/R-manual/R-devel/library/mgcv/html/concurvity.html:



          "Concurvity occurs when some smooth term in a model could be approximated by     
          one or more of the other smooth terms in the model. This is often the case
          when a smooth of space is included in a model, along with smooths of other
          covariates that also vary more or less smoothly in space. Similarly it tends
          to be an issue in models including a smooth of time, along with smooths of
          other time varying covariates.

          Concurvity can be viewed as a generalization of co-linearity, and causes
          similar problems of interpretation. It can also make estimates somewhat
          unstable (so that they become sensitive to apparently innocuous modelling
          details, for example)."


          The above link explains how you can compute three different measures of concurvity for a GAM model fitted with the mgcv package in R, all of which are bounded between 0 and 1 (with 0 indicating no concurvity).



          Thus, you do have to check for the potential presence of concurvity in your GAM models by computing appropriate measures of concurvity and making sure they are not too high (i.e., not too close to 1). See also gam smoother vs parametric term (concurvity difference), https://jroy042.github.io/nonlinear/week3.html and https://eric-pedersen.github.io/mgcv-esa-workshop/slides/02-model_checking.html#/.






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            $begingroup$

            GAM models can be afflicted by concurvity (the extension of GLM collinearity to GAM models).



            According to https://stat.ethz.ch/R-manual/R-devel/library/mgcv/html/concurvity.html:



            "Concurvity occurs when some smooth term in a model could be approximated by     
            one or more of the other smooth terms in the model. This is often the case
            when a smooth of space is included in a model, along with smooths of other
            covariates that also vary more or less smoothly in space. Similarly it tends
            to be an issue in models including a smooth of time, along with smooths of
            other time varying covariates.

            Concurvity can be viewed as a generalization of co-linearity, and causes
            similar problems of interpretation. It can also make estimates somewhat
            unstable (so that they become sensitive to apparently innocuous modelling
            details, for example)."


            The above link explains how you can compute three different measures of concurvity for a GAM model fitted with the mgcv package in R, all of which are bounded between 0 and 1 (with 0 indicating no concurvity).



            Thus, you do have to check for the potential presence of concurvity in your GAM models by computing appropriate measures of concurvity and making sure they are not too high (i.e., not too close to 1). See also gam smoother vs parametric term (concurvity difference), https://jroy042.github.io/nonlinear/week3.html and https://eric-pedersen.github.io/mgcv-esa-workshop/slides/02-model_checking.html#/.






            share|cite|improve this answer











            $endgroup$


















              2












              $begingroup$

              GAM models can be afflicted by concurvity (the extension of GLM collinearity to GAM models).



              According to https://stat.ethz.ch/R-manual/R-devel/library/mgcv/html/concurvity.html:



              "Concurvity occurs when some smooth term in a model could be approximated by     
              one or more of the other smooth terms in the model. This is often the case
              when a smooth of space is included in a model, along with smooths of other
              covariates that also vary more or less smoothly in space. Similarly it tends
              to be an issue in models including a smooth of time, along with smooths of
              other time varying covariates.

              Concurvity can be viewed as a generalization of co-linearity, and causes
              similar problems of interpretation. It can also make estimates somewhat
              unstable (so that they become sensitive to apparently innocuous modelling
              details, for example)."


              The above link explains how you can compute three different measures of concurvity for a GAM model fitted with the mgcv package in R, all of which are bounded between 0 and 1 (with 0 indicating no concurvity).



              Thus, you do have to check for the potential presence of concurvity in your GAM models by computing appropriate measures of concurvity and making sure they are not too high (i.e., not too close to 1). See also gam smoother vs parametric term (concurvity difference), https://jroy042.github.io/nonlinear/week3.html and https://eric-pedersen.github.io/mgcv-esa-workshop/slides/02-model_checking.html#/.






              share|cite|improve this answer











              $endgroup$
















                2












                2








                2





                $begingroup$

                GAM models can be afflicted by concurvity (the extension of GLM collinearity to GAM models).



                According to https://stat.ethz.ch/R-manual/R-devel/library/mgcv/html/concurvity.html:



                "Concurvity occurs when some smooth term in a model could be approximated by     
                one or more of the other smooth terms in the model. This is often the case
                when a smooth of space is included in a model, along with smooths of other
                covariates that also vary more or less smoothly in space. Similarly it tends
                to be an issue in models including a smooth of time, along with smooths of
                other time varying covariates.

                Concurvity can be viewed as a generalization of co-linearity, and causes
                similar problems of interpretation. It can also make estimates somewhat
                unstable (so that they become sensitive to apparently innocuous modelling
                details, for example)."


                The above link explains how you can compute three different measures of concurvity for a GAM model fitted with the mgcv package in R, all of which are bounded between 0 and 1 (with 0 indicating no concurvity).



                Thus, you do have to check for the potential presence of concurvity in your GAM models by computing appropriate measures of concurvity and making sure they are not too high (i.e., not too close to 1). See also gam smoother vs parametric term (concurvity difference), https://jroy042.github.io/nonlinear/week3.html and https://eric-pedersen.github.io/mgcv-esa-workshop/slides/02-model_checking.html#/.






                share|cite|improve this answer











                $endgroup$



                GAM models can be afflicted by concurvity (the extension of GLM collinearity to GAM models).



                According to https://stat.ethz.ch/R-manual/R-devel/library/mgcv/html/concurvity.html:



                "Concurvity occurs when some smooth term in a model could be approximated by     
                one or more of the other smooth terms in the model. This is often the case
                when a smooth of space is included in a model, along with smooths of other
                covariates that also vary more or less smoothly in space. Similarly it tends
                to be an issue in models including a smooth of time, along with smooths of
                other time varying covariates.

                Concurvity can be viewed as a generalization of co-linearity, and causes
                similar problems of interpretation. It can also make estimates somewhat
                unstable (so that they become sensitive to apparently innocuous modelling
                details, for example)."


                The above link explains how you can compute three different measures of concurvity for a GAM model fitted with the mgcv package in R, all of which are bounded between 0 and 1 (with 0 indicating no concurvity).



                Thus, you do have to check for the potential presence of concurvity in your GAM models by computing appropriate measures of concurvity and making sure they are not too high (i.e., not too close to 1). See also gam smoother vs parametric term (concurvity difference), https://jroy042.github.io/nonlinear/week3.html and https://eric-pedersen.github.io/mgcv-esa-workshop/slides/02-model_checking.html#/.







                share|cite|improve this answer














                share|cite|improve this answer



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                edited 1 hour ago

























                answered 1 hour ago









                Isabella GhementIsabella Ghement

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