I am trying to run a Generalized linear mixed model (GLMM) on r, I have two fixed factors and two random factors
however there are a lot of holes in my data set and the I am struggling to find a code to run the glmm all I found is the glm
Can someone please walk me through this, I know very little about R and coding
You can use the lme4 package as well. The command for a generalized linear mixed model is glmer().
Example:
install.packages("lme4") #If you still haven't done it.
library(lme4)
myfirstmodel <- glmer(variable_to_study ~ fixed_variable + (1|random_effect_varible), data = mydataset, family = poisson)
Family = poisson was just an example. Choose the 'family' according to the nature of the variable_to_study (eg. poisson for discrete data).
Related
I would like to estimate a random effects (RE) multinomial logit model.
I have been applying mblogit from the mclogit package. However, once I introduce RE into my model, it fails to converge.
Is there a workaround this?
For instance, I tried to adjust the fitting process of mblogit and increase the maximal number of iterations (maxit), but did not succeed to correctly write the syntax for the control function. Would this be the right approach? And if so, could you advise me how to implement it into my model which so far looks as follows:
meta.mblogit <- mblogit(Migration ~ ClimateHazard4 , weights = logNsquare,
data = meta.df, subset= Panel==1, random = ~1|StudyID,
)
Here, both variables (Migration and ClimateHazard4) are factor variables.
Or is there an alternative approach you could recommend me for an estimation of RE multinomial logit?
Thank you very much!
I am trying to fit a linear growth model (LGM) in R, and I understand that the primary steps would be to fit a Null model with time as a predictor of my independent variable Y (allowing for random effects) and a Null model not allowing for random effects, then compare the two and see whether the random effect is strong enough to justify the usage of the model with random intercept.
I managed to fit the model with random intercept with the lmer function of the lme4 package, but I can't find a function in that package that allows me to fit a model without random intercept.
I have tried to fit models both with random intercept (lme function) and without (gls function) with the nlme package, but neither of them have been working for me.
My original code was:
library(nlme)
LMModel <- lme(Y~Time, random=~Time| ID, data=dataset,
method="ML")
and running that, I got an error saying "missing values in object" (apparently referring to my Time variable). I thus added a transformation of my dataset into a matrix with "matr <- as.matrix(dataset)" and added the missing data management part to my code, which ended up being:
LMModel <- lme(Y~Time, random=~Time| ID, data=dataset,
method="ML", na.action = na.exclude(matr))
Running this, I get the error: ' could not find function "1" '
I further tried to fit a model with no random effect with the gls function of nlme and got the exact same error.
I feel quite lost as I can't seem to figure out what that function 1 means. Any ideas of what might be happening here?
Thanks a lot in advance for the help!
Federico
I am new to R and am trying to reproduce results from my SPSS analyses, but seem to be missing something.
I am trying to run a linear mixed effects model using gls in the nlme package.
The SPSS syntax I am trying to reproduce is:
MIXED Satisfaction_A BY Role
/FIXED=Role | NOINT SSTYPE(3)
/METHOD=ML
/PRINT=SOLUTION TESTCOV
/RANDOM=Role | SUBJECT(focalid) COVTYPE(UNR)
/REPEATED=Role | SUBJECT(dyadid*focalid) COVTYPE(UNR).
Essentially, it is a two-intercept model with nested data where Focal ID is the level-2/nesting variable which contains 2 responses for Satisfaction, distinguished by Role.
The R code I have so far is:
gls(Satisfaction_A ~ Role -1, #Two-intercept approach
data = chlpairwise,
correlation = corSymm(form = ~1|focalid/dyadid),
weights = varIdent(form = ~1|Role),
method = "ML",
na.action = na.omit)
The regression coefficients are very similar to those from SPSS. But what am I missing in the code so that I can view the Covariance Parameters like in SPSS? SPSS Covariance Parameters
Many thanks! I hope to keep learning so that I can eventually give back to this community for all of the help I have received. :)
Probably you need to use the function getVarCov() that returns the marginal covariance matrix from a fitted marginal model. It will also work if you fit a linear mixed effects model using function lme().
A newbie question: does anyone know how to run a logistic regression with clustered standard errors in R? In Stata it's just logit Y X1 X2 X3, vce(cluster Z), but unfortunately I haven't figured out how to do the same analysis in R. Thanks in advance!
You might want to look at the rms (regression modelling strategies) package. So, lrm is logistic regression model, and if fit is the name of your output, you'd have something like this:
fit=lrm(disease ~ age + study + rcs(bmi,3), x=T, y=T, data=dataf)
fit
robcov(fit, cluster=dataf$id)
bootcov(fit,cluster=dataf$id)
You have to specify x=T, y=T in the model statement. rcs indicates restricted cubic splines with 3 knots.
Another alternative would be to use the sandwich and lmtest package as follows. Suppose that z is a column with the cluster indicators in your dataset dat. Then
# load libraries
library("sandwich")
library("lmtest")
# fit the logistic regression
fit = glm(y ~ x, data = dat, family = binomial)
# get results with clustered standard errors (of type HC0)
coeftest(fit, vcov. = vcovCL(fit, cluster = dat$z, type = "HC0"))
will do the job.
I have been banging my head against this problem for the past two days; I magically found what appears to be a new package which seems destined for great things--for example, I am also running in my analysis some cluster-robust Tobit models, and this package has that functionality built in as well. Not to mention the syntax is much cleaner than in all the other solutions I've seen (we're talking near-Stata levels of clean).
So for your toy example, I'd run:
library(Zelig)
logit<-zelig(Y~X1+X2+X3,data=data,model="logit",robust=T,cluster="Z")
Et voilà!
There is a command glm.cluster in the R package miceadds which seems to give the same results for logistic regression as Stata does with the option vce(cluster). See the documentation here.
In one of the examples on this page, the commands
mod2 <- miceadds::glm.cluster(data=dat, formula=highmath ~ hisei + female,
cluster="idschool", family="binomial")
summary(mod2)
give the same robust standard errors as the Stata command
logit highmath hisei female, vce(cluster idschool)
e.g. a standard error of 0.004038 for the variable hisei.
I have fit my discrete count data using a variety of functions for comparison. I fit a GEE model using geepack, a linear mixed effect model on the log(count) using lme (nlme), a GLMM using glmer (lme4), and a GAMM using gamm4 (gamm4) in R.
I am interested in comparing these models and would like to plot the expected (predicted) values for a new set of data (predictor variables). My goal is to compare the predicted effects for each model under particular conditions (x variables). Of particular interest is the comparison between marginal (GEE) and conditional estimates.
I think my main problem might be getting the new data in the correct form with the correct labels and attributes and such. I am still very much an R novice and struggle with this stuff (no course on this at my university unfortunately).
I currently have fitted models
gee1 lme1 lmer1 gamm1
and can extract their fixed effect coefficients and standard errors without a problem. I also don't have a problem converting them from the log scale or estimating confidence intervals accounting for the random effects.
I also have my new dataframe newdat which has 365 observations of 23 variables (average environmental data for each day of the year).
I am stuck on how to predict new count estimates from this. I played around with the model.matrix function but couldn't get it to work. For example, I tried:
mm = model.matrix(terms(glmm1), newdat) # Error in model.frame.default(object,
# data, xlev = xlev) : object is not a matrix
newdat$pcount = mm %*% fixef(glmm1)
Any suggestions or good references would be greatly appreciated. Can anyone help with the error above?
Getting predictions for lme() and lmer() is documented on http://glmm.wikidot.com/faq