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Ridge regression vs Lasso Regression


Is Lasso regression or Elastic-net regression always better than the ridge regression?

I've conducted these regressions on a few data sets and I've always got the same result that the mean squared error is the least in lasso regression. Is this a mere coincidence or is this true in any case?


Solution

  • On the topic, James, Witten, Hastie and Tibshirani write in their book "An Introduktion to Statistical Learning":

    These two examples illustrate that neither ridge regression nor the lasso will universally dominate the other. In general, one might expect the lasso to perform better in a setting where a relatively small number of predictorshave substantial coefficients, and the remaining predictors have coefficients that are very small or that equal zero. Ridge regression will perform better when the response is a function of many predictors, all with coefficients of roughly equal size. However, the number of predictors that is related to the response is never known apriori for real data sets. A technique such as cross-validation can be used in order to determine which approach is betteron a particular data set. (chapter 6.2)