Abstract
Generalized linear mixed models are a widely used tool for modeling longitudinal data. However, their use is typically restricted to few covariates, because the presence of many predictors yields unstable estimates. The presented approach to the fitting of generalized linear mixed models includes an L 1-penalty term that enforces variable selection and shrinkage simultaneously. A gradient ascent algorithm is proposed that allows to maximize the penalized log-likelihood yielding models with reduced complexity. In contrast to common procedures it can be used in high-dimensional settings where a large number of potentially influential explanatory variables is available. The method is investigated in simulation studies and illustrated by use of real data sets.
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Akaike, H.: Information theory and the extension of the maximum likelihood principle. In: Second International Symposium on Information Theory, pp. 267–281 (1973)
Bates, D., Maechler, M.: lme4: linear mixed-effects models using S4 classes. R package version 0.999375-34 (2010)
Bondell, H.D., Krishna, A., Ghosh, S.K.: Joint variable selection of fixed and random effects in linear mixed-effects models. Biometrics 66, 1069–1077 (2010)
Booth, J.G.: Bootstrap methods for generalized mixed models with applications to small area estimation. In: Seeber, G.U.H., Francis, B.J., Hatzinger, R., Steckel-Berger, G. (eds.) Statistical Modelling, vol. 104, pp. 43–51. Springer, New York (1996)
Booth, J.G., Hobert, J.P.: Maximizing generalized linear mixed model likelihoods with an automated Monte Carlo EM algorithm. J. R. Stat. Soc. B 61, 265–285 (1999)
Breiman, L.: Heuristics of instability and stabilization in model selection. Ann. Stat. 6, 2350–2383 (1996)
Breiman, L.: Arcing classifiers. Ann. Stat. 26, 801–849 (1998)
Breslow, N.E., Clayton, D.G.: Approximate inference in generalized linear mixed model. J. Am. Stat. Assoc. 88, 9–25 (1993)
Breslow, N.E., Lin, X.: Bias correction in generalized linear mixed models with a single component of dispersion. Biometrika 82, 81–91 (1995)
Broström, G.: glmmML: generalized linear models with clustering. R package version 0.81-6 (2009)
Bühlmann, P., Hothorn, T.: Boosting algorithms: regularization, prediction and model fitting. Stat. Sci. 22, 477–522 (2007)
Bühlmann, P., Yu, B.: Boosting with the L2 loss: regression and classification. J. Am. Stat. Assoc. 98, 324–339 (2003)
Candes, E., Tao, T.: The Dantzig selector: statistical estimation when p is much larger than n. Ann. Stat. 35, 2313–2351 (2007)
Chatterjee, A., Lahiri, S.N.: Bootstrapping lasso estimators. J. Am. Stat. Assoc. 106, 608–625 (2011)
Davison, A.C., Hinkley, D.V.: Bootstrap Methods and Their Application. Cambridge University Press, Cambridge (1997)
Efron, B.: The Jackknife, the Bootstrap and Other Resampling Plans. SIAM: CBMS-NSF Regional Conference Series in Applied Mathematics, vol. 38. (1982)
Efron, B.: Estimating the error rate of a prediction rule: improvement on crossvalidation. J. Am. Stat. Assoc. 78, 316–331 (1983)
Efron, B.: How biased is the apparent error rate of a prediction rule? J. Am. Stat. Assoc. 81, 461–470 (1986)
Efron, B., Tibshirani, R.: An Introduction to the Bootstrap. Chapman & Hall, New York (1993)
Efron, B., Hastie, T., Johnstone, I., Tibshirani, R.: Least angle regression. Ann. Stat. 32, 407–499 (2004)
Fahrmeir, L., Lang, S.: Bayesian inference for generalized additive mixed models based on Markov random field priors. Appl. Stat. 50, 201–220 (2001). doi:10.1111/1467-9876.00229
Fahrmeir, L., Tutz, G.: Multivariate Statistical Modelling Based on Generalized Linear Models, 2nd edn. Springer, New York (2001)
Fan, J., Li, R.: Variable selection via nonconcave penalize likelihood and its oracle properties. J. Am. Stat. Assoc. 96, 1348–1360 (2001)
Freund, Y., Schapire, R.E.: Experiments with a new boosting algorithm. In: Proceedings of the Thirteenth International Conference on Machine Learning, pp. 148–156. Morgan Kaufmann, San Francisco (1996)
Friedman, J.H.: Greedy function approximation: a gradient boosting machine. Ann. Stat. 29, 337–407 (2001)
Geissler, S.: The predictive sample reuse method with applications. J. Am. Stat. Assoc. 70, 320–328 (1975)
Genkin, A., Lewis, D., Madigan, D.: Large-scale Bayesian logistic regression for text categorization. Technometrics 49, 291–304 (2007)
Goeman, J.J.: L1 penalized estimation in the Cox proportional hazards model. Biom. J. 52, 70–84 (2010)
Groll, A.: glmmLasso: Variable Selection for Generalized Linear Mixed Models by L1-penalized Estimation. R package version 1.0.1 (2011a)
Groll, A.: GMMBoost: Componentwise Likelihood-based Boosting Approaches to Generalized Mixed Models. R package version 1.0.2 (2011b)
Gui, J., Li, H.Z.: Penalized Cox regression analysis in the high-dimensional and low-sample size settings, with applications to microarray gene expression data. Bioinformatics 21, 3001–3008 (2005)
Hastie, T., Rosset, S., Tibshirani, R., Zhu, J.: The entire regularization path for the support vector machine. J. Mach. Learn. Res. 5, 1391–1415 (2004)
Ibrahim, J.G., Zhu, H., Garcia, R.I., Guo, R.: Fixed and random effects selection in mixed effects models. Biometrics 67, 495–503 (2011)
James, G.M., Radchenko, P.: A generalized Dantzig selector with shrinkage tuning. Biometrika 96(2), 323–337 (2009)
Kim, Y., Kim, J.: Gradient lasso for feature selection. In: Proceedings of the 21st International Conference on Machine Learning. ACM International Conference Proceeding Series, vol. 69, pp. 473–480 (2004)
Kneib, T., Hothorn, T., Tutz, G.: Variable selection and model choice in geoadditive regression. Biometrics 65, 626–634 (2009)
Lesaffre, E., Asefa, M., Verbeke, G.: Assessing the godness-of-fit of the laird and ware model—an example: the Jimma infant survival differential longitudinal study. Stat. Med. 18, 835–854 (1999)
Lin, X., Breslow, N.E.: Bias correction in generalized linear mixed models with multiple components of dispersion. J. Am. Stat. Assoc. 91, 1007–1016 (1996)
Littell, R., Milliken, G., Stroup, W., Wolfinger, R.: SAS System for Mixed Models. SAS Institute Inc., Cary (1996)
McCullagh, P.: Re-sampling and exchangeable arrays. Bernoulli 6, 303–322 (2000)
McCulloch, C.E., Searle, S.R., Neuhaus, J.M.: Generalized, Linear and Mixed Models, 2nd edn. Wiley, New York (2008)
Meier, L., Van de Geer, S., Bühlmann, P.: The group lasso for logistic regression. J. R. Stat. Soc. B 70, 53–71 (2008)
Ni, X., Zhang, D., Zhang, H.H.: Variable selection for semiparametric mixed models in longitudinal studies. Biometrics 66, 79–88 (2010)
Osborne, M., Presnell, B., Turlach, B.: On the lasso and its dual. J. Comput. Graph. Stat. (2000)
Park, M.Y., Hastie, T.: L1-regularization path algorithm for generalized linear models. J. R. Stat. Soc. B 19, 659–677 (2007)
Picard, R., Cook, D.: Cross-validation of regression models. J. Am. Stat. Assoc. 79, 575–583 (1984)
Pinheiro, J.C., Bates, D.M.: Mixed-Effects Models in S and S-Plus. Springer, New York (2000)
Radchenko, P., James, G.M.: Variable inclusion and shrinkage algorithms. J. Am. Stat. Assoc. 103, 1304–1315 (2008)
Schall, R.: Estimation in generalised linear models with random effects. Biometrika 78, 719–727 (1991)
Schelldorfer, J.: lmmlasso: Linear mixed-effects models with Lasso. R package version 0.1-2. (2011)
Schelldorfer, J., Bühlmann, P.: GLMMLasso: an algorithm for high-dimensional generalized linear mixed models using L1-penalization. Preprint, ETH Zurich, (2011). http://stat.ethz.ch/people/schell
Schelldorfer, J., Bühlmann, P., van de Geer, S.: Estimation for high-dimensional linear mixed-effects models using L1-penalization. Scand. J. Stat. 38(2), 197–214 (2011)
Schwarz, G.: Estimating the dimension of a model. Ann. Stat. 6, 461–464 (1978)
Segal, M.R.: Microarray gene expression data with linked survival phenotypes: diffuse large-b-cell lymphoma revisited. Biostatistics 7, 268–285 (2006)
Shang, J., Cavanaugh, J.E.: Bootstrap variants of the Akaike information criterion for mixed model selection. Comput. Stat. Data Anal. 52, 2004–2021 (2008)
Shevade, S.K., Keerthi, S.S.: A simple and efficient algorithm for gene selection using sparse logistic regression. Bioinformatics 19, 2246–2253 (2003)
Stone, M.: Cross-validatory choice and assessment of statistical predictions (with discussion). J. R. Stat. Soc. B 36, 111–147 (1974)
Stone, M.: Cross-validation: A review. Math. Oper.forsch. Stat. 9, 127–139 (1978)
Tibshirani, R.: Regression shrinkage and selection via the lasso. J. R. Stat. Soc. B 58, 267–288 (1996)
Tibshirani, R.: The lasso method for variable selection in the Cox model. Stat. Med. 16, 385–395 (1997)
Tutz, G., Groll, A.: Generalized linear mixed models based on boosting. In: Kneib, T., Tutz, G. (eds.) Statistical Modelling and Regression Structures—Festschrift in the Honour of Ludwig Fahrmeir. Physica, Heidelberg (2010)
Tutz, G., Groll, A.: Likelihood-based boosting in binary and ordinal random effects models. J. Comput. Graph. Stat. (2012). doi:10.1080/10618600.2012.694769
Tutz, G., Reithinger, F.: A boosting approach to flexible semiparametric mixed models. Stat. Med. 26, 2872–2900 (2007)
Venables, W.N., Ripley, B.D.: Modern Applied Statistics with S, 4th edn. Springer, New York (2002)
Vonesh, E.F.: A note on the use of Laplace’s approximation for nonlinear mixed-effects models. Biometrika 83, 447–452 (1996)
Wang, D., Eskridge, K.M., Crossa, J.: Identifying QTLs and epistasis in structured plant populations using adaptive mixed lasso. J. Agric. Biol. Environ. Stat. 16, 170–184 (2010a)
Wang, S., Song, P.X., Zhu, J.: Doubly regularized REML for estimation and selection of fixed and random effects in linear mixed-effects models. Technical Report 89, The University of Michigan, (2010b)
Wolfinger, R.W.: Laplace’s approximation for nonlinear mixed models. Biometrika 80, 791–795 (1994)
Wolfinger, R., O’Connell, M.: Generalized linear mixed models; a pseudolikelihood approach. J. Stat. Comput. Simul. 48, 233–243 (1993)
Wood, S.N.: Generalized Additive Models: An Introduction with R. Chapman & Hall, London (2006)
Yang, H.: Variable selection procedures for generalized linear mixed models in longitudinal data analysis. PhD thesis, North Carolina State University (2007)
Yuan, M., Lin, Y.: Model selection and estimation in regression with grouped variables. J. R. Stat. Soc. B 68, 49–67 (2006)
Zhao, P., Rocha, G., Yu, B.: The composite absolute penalties family for grouped and hierarchical variable selection. Ann. Stat. 37, 3468–3497 (2009)
Zou, H., Hastie, T.: Regularization and variable selection via the elastic net. J. R. Stat. Soc. B 67, 301–320 (2005)
Zou, H., Hastie, T.: The adaptive lasso and its oracle properties. J. Am. Stat. Assoc. 101, 1418–1429 (2006)
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Appendices
Appendix A: Determination of the tuning parameter λ
First of all, define a fine grid of different values for the tuning parameter, 0≤λ 1≤⋯≤λ L ≤∞. Next, the optimal tuning parameter is determined using one of the following techniques and finally, the whole data set is fitted again using the glmmLasso algorithm with λ opt to obtain the final estimates \(\hat{\boldsymbol {\delta }}, \hat{\textbf {Q}}\) and the corresponding fit \(\hat{{\boldsymbol {\mu }}}\).
One way to determine the tuning parameter is based on information criteria. In the following we focus on Akaike’s information criterion (AIC, see Akaike 1973) as well as on the Bayesian information criterion (BIC, see Schwarz 1978), also known as Schwarz’s information criterion, given by:
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j∈{1,…,L}, where \(l(\hat{{\boldsymbol {\mu }}}^{(j)})\) denotes the approximated log-likelihood from (4) evaluated at the fit corresponding to λ j and df(λ j ) denotes the degrees of freedom, which are equal to the sum of the number of nonzero fixed-effects coefficients and the number of covariance parameters, that is \(df(\lambda_{j})=\#\{k:1\leq k\leq p, \hat{\beta}_{k}\neq0\}+\frac{q(q+1)}{2}\) (compare Schelldorfer and Bühlmann 2011). Finally, for the optimal tuning parameter λ opt the chosen information criterion is minimal.
Alternatively to information criteria, the optimal tuning parameter λ opt can be derived using K-fold cross-validation. For this purpose the original sample is randomly partitioned into K subsamples and the model is fitted on K−1 subsamples (training data). The remaining subsample (test data) is used for validation. The adequacy of the model for λ j ,j∈{1,…,L} can be assessed by evaluating a cross-validation score on the test data, for example, the deviance
where l i (⋅) denotes the log-likelihood contribution of sample element i. In special situations other measures of fit can also be used, for example the misclassification error rate for binary responses or the mean squared error for continuous responses. The procedure is then repeated K times, with each subsample used exactly once as test data. For the optimal tuning parameter the cross-validation score averaged over all K folds is minimal. The concept of splitting the data into parts has a long history and has already been discussed, for example, by Stone (1974, 1978), Geissler (1975) and Picard and Cook (1984).
Appendix B: Partition of Fisher matrix
According to Fahrmeir and Tutz (2001) the penalized pseudo-Fisher matrix F pen(δ)=A T W(δ)A+K can be partitioned into
with single components
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and D i (δ)=∂h(η i )/∂ η, Σ i (δ)=cov(y i |β,b i ).
Appendix C: Two bootstrap approaches for GLMMs
The general idea of bootstrapping has been developed by Efron (1983, 1986). An extensive overview of the bootstrap and related methods for asserting statistical accuracy can be found in Efron and Tibshirani (1993). For GLMMs two main approaches are found in the literature. The first approach is to resample nonparametrically, which has been proposed e.g. by McCullagh (2000) and Davison and Hinkley (1997). They randomly sample groups of observations with replacement at the first stage and suggest various ways how to sample within the groups at the second stage. They showed that sometimes it can be useful to randomly resample groups at the first stage only and leave groups themselves unchanged, for example if there is a longitudinal structure in the data, see e.g. Shang and Cavanaugh (2008).
The second approach, on which the standard errors in Sect. 4 are based on, is to simulate parametric bootstrap samples following the parametric distribution family of the underlying model (compare Efron 1982). Booth (1996) has extended the parametric approach from Efron (1982) to GLMMs to estimate standard errors for the fitted linear predictor \(\hat{{\boldsymbol {\eta }}}=\textbf {X}{\hat{{\boldsymbol {\beta }}}}+\textbf {Z}\hat{\textbf {b}}\) from Sect. 2.
Analogously we can derive standard errors for the fixed effects estimate \(\hat{{\boldsymbol {\beta }}}\) and for the estimated random effects variance components \(\hat{\textbf {Q}}\), respectively. Let {F ξ :ξ∈Ξ} denote the parametric distribution family of the underlying model, where ξ T=(β T,vec(Q)T) is unknown. Here vec(Q) denotes the column-wise vectorization of matrix Q to a column vector. Let \(\hat{{\boldsymbol {\xi }}}=(\hat{{\boldsymbol {\beta }}}^{T},\mathrm{vec}(\hat{\textbf {Q}})^{T})\) denote the Lasso estimate of ξ for an already chosen penalty parameter λ on a certain data set. Now we can simulate new bootstrap data sets (y ∗,b ∗) with respect to the distribution \(F_{\hat{{\boldsymbol {\xi }}}}\), i.e. \((\textbf {y}^{*},\textbf {b}^{*})\sim F_{\hat{{\boldsymbol {\xi }}}}\). We repeat this procedure sufficiently often, say B=10.000, and fit every new bootstrap data set \((\textbf {y}^{*}_{(r)},\textbf {X},\textbf {W})\), r=1,…,B, with our glmmLasso algorithm. The new fits \(\hat{{\boldsymbol {\xi }}}_{(r)}^{*}\) corresponding to the r-th new data set serve as bootstrap estimates and can be used to derive standard errors.
Although consistency of straightforward bootstrap in L 1-penalized regression can fail even in the simple case of linear regression (Chatterjee and Lahiri 2011), in the finite dimensional case bootstrap is helpful and we found that it yields reasonable results.
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Groll, A., Tutz, G. Variable selection for generalized linear mixed models by L 1-penalized estimation. Stat Comput 24, 137–154 (2014). https://doi.org/10.1007/s11222-012-9359-z
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DOI: https://doi.org/10.1007/s11222-012-9359-z