Help : glm p-values for a factor predictor
Thank you for your answer.
The used code is the next one :
champ_model<-c("y","categ_juridique","Indic_CTRLAUTRE_RPOS","Indic_CTRLAUTRE_RNEG","Indic_CTRLCCA_RPOS",
"Indic_CTRLCCA_RNEG","Indic_CTRLCPAP_RPOS","Indic_CTRLCPAP_RNEG","Indic_CTRLLCTI_RPOS",
"Indic_Changement_NomLogiciel","Indic_Changement_NomEditeur","Changt_NomEditeurPaie",
"Changt_NomLogicielPaie","Infoabs_NomEditeurPaie","Infoabs_NomLogicielPaie",
"Indic_Decla_comple","Indic_Decla_AnnuRempl","class_ape","class_Logiciel","class_Editeur",
"moda_delai_soldeN_1","moda_delai_soldeN_2","moda_delai_soldeN_3","moda_delai_soldeN_4",
"moda_delai_soldeN_5",
"moda_anciennete_debitN_1","moda_anciennete_debitN_2","moda_anciennete_debitN_3",
"moda_anciennete_debitN_4","moda_anciennete_debitN_5",
"moda_moy_anciennete_debit","moda_std_anciennete_debit",
"moda_moy_delai_solde","moda_std_delai_solde",
var_cluster_Arome,var_cluster_BRC,var_cluster_Cedre,var_cluster_cntx2,var_cluster_ctrl,
var_cluster_DADS_assiette2,var_cluster_DADS_avantage2,var_cluster_DADS_contrat2,
var_cluster_DADS_salarie2,var_cluster_Sequoia)
--> The predictors between quotes (excepted y) are qualitative ; others
are groups of continuous predictors
Var_model<-paste0("y ~ ", paste(champ_model_cont[-1],collapse=" + "))
Logit_appr<-glm(formula=Var_model,family=binomial(link="logit"),data=pop_ctrl_siren_cca2017_appr)
--> The results of this glm do not provide overall pvalues for the
qualitative predictors, only one pvalue by modality. And for selecting the
qualitative predictors, i need that overall pvalue that SAS for example
provides with PROC LOGISTIC.
Benoit Pel?.
De : "Bob O'Hara" <rni.boh at gmail.com>
A : Beno?t PELE <benoit.pele at acoss.fr>,
Cc : r-help <r-help at r-project.org>
Date : 29/06/2017 11:46
Objet : Re: [R] Help : glm p-values for a factor predictor
It might help if you provided the code you used. It's possible that
you didn't use direction="backward" in stepAIC(). Or if you did, it
was still running, so whatever else you try will still be slow. The
statement "R provides only the pvalues for each level" is wrong: look
at the anova() function.
Bob
On 29 June 2017 at 11:13, Beno?t PELE <benoit.pele at acoss.fr> wrote:
Hello, i am a newby on R and i am trying to make a backward selection on a binomial-logit glm on a large dataset (69000 lines for 145 predictors). After 3 days working, the stepAIC function did not terminate. I do not know if that is normal but i would like to try computing a "homemade" backward with a repeated glm ; at each step, the predictor with the max pvalue would be excluded until reaching a set of 20 predictors for example. My question is about the factor predictors with several levels. R
provides
only the pvalues for each level whereas i need an overall pvalue for
testing the predictor.
On internet, the only solution i found suggests to compute a Khi2
log-likelihood test between the complete model and the model without the
factor predictor to emphasize its relevance.
Do you know other ways? Another R package managing this kind of issue?
Thank you and best regards, Benoit.
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