I'm constructing a piecewise structural equation model using the piecewiseSEM package in R (Lefcheck - https://cran.r-project.org/web/packages/piecewiseSEM/vignettes/piecewiseSEM.html)
I already created the model set and I could evaluate the model fit, so the model itself works. Also, the data fits the model (p = 0.528).
But I do not succeed in extracting the path coefficients.
This is the error i get: Error in cbind(Xlarge, Xsmall) : number of rows of matrices must match (see arg 2)
I already tried (but this did not work):
standardising my data because of the warning: Some predictor variables are on very different scales: consider rescaling
adapted my data (threw some NA values away)
This is my modellist:
predatielijst = list(
lmer(plantgrootte ~ gapfraction + olsen_P + (1|plot_ID), data = d),
glmer(piek1 ~ gapfraction + olsen_P + plantgrootte + (1|plot_ID),
family = poisson, data = d),
glmer(predatie ~ piek1 + (1|plot_ID), family = binomial, data = d)
)
with "predatie" being a binary variable (yes or no) and all the rest continuous variables (gapfraction, plantgrootte, olsen_P & piek1)
Thanks in advance!
Try installing the development version:
library(devtools)
install_github("jslefche/piecewiseSEM#2.0")
Replace list with psem and run the coefs or summary function. It will likely get rid of your error. If not, open a bug on Github!
WARNING: this will overwrite your current version from CRAN. You will need to reinstall from CRAN to get version 1.4 back.
try to use lme (out of the nlme library) ilstead of glmer. As far as I understand, the fact that lmer does not provide p-values (while lme does) seems to be the problem here.
Hope this works.
Related
I am running a negative binomial regression on my dataset using the glm.nb() function.
My model looks something like this:
m_nb= glm.nb(Error_Count ~ TotalWL + Auto_frac +PHONE+JUSTIF_weight + MESSAGE_OTHER_count + Hour+
I(Auto_frac^2)+I(TotalWL^2), data = df)
When I ran it with a dataset of 10,000, the model is able to run, however, when I ran it with a larger dataset (60,000), I got this error:
`Error: no valid set of coefficients has been found: please supply starting values`
I then tried to give it some start values, but still throw the same error
m_nb= glm.nb(Error_Count ~ TotalWL + Auto_frac +PHONE+JUSTIF_weight + MESSAGE_OTHER_count + Hour+
I(Auto_frac^2)+I(TotalWL^2), data = df, start = c(0.02, 0.3,0.2,3,43, 4,13,0.04, 100))
Error: cannot find valid starting values: please specify some
But the model still doesn't converge. How should I set the starting value?
I also tried the same model with the fenebin() function in the fixest pacakage and the model works. However, I need the glm package, since the fixest package does not provide the standard error (S.E.) in the predict().
Thank you.
When trying to graph the conditional fixed effects of a glmmTMB model with two random intercepts in GGally I get the error:
There was an error calling "tidy_fun()". Most likely, this is because the
function supplied in "tidy_fun=" was misspelled, does not exist, is not
compatible with your object, or was missing necessary arguments (e.g. "conf.level=" or "conf.int="). See error message below.
Error: Error in "stop_vctrs()":
! Can't recycle "..1" (size 3) to match "..2" (size 2).`
I have tinkered with figuring out the issue and it seems to be related to the two random intercepts included in the model. I have also tried extracting the coefficient and standard error information separately through broom.mixed::tidy and then feeding the data frame into GGally:ggcoef() with no avail. Any suggestions?
# Example with built-in randu data set
data(randu)
randu$A <- factor(rep(c(1,2), 200))
randu$B <- factor(rep(c(1,2,3,4), 100))
# Model
test <- glmmTMB(y ~ x + z + (0 +x|A) + (1|B), family="gaussian", data=randu)
# A few of my attempts at graphing--works fine when only one random effects term is in model
ggcoef_model(test)
ggcoef_model(test, tidy_fun = broom.mixed::tidy)
ggcoef_model(test, tidy_fun = broom.mixed::tidy, conf.int = T, intercept=F)
ggcoef_model(test, tidy_fun = broom.mixed::tidy(test, effects="fixed", component = "cond", conf.int = TRUE))
There are some (old!) bugs that have recently been fixed (here, here) that would make confidence interval reporting on RE parameters break for any model with multiple random terms (I think). I believe that if you are able to install updated versions of both glmmTMB and broom.mixed:
remotes::install_github("glmmTMB/glmmTMB/glmmTMB#ci_tweaks")
remotes::install_github("bbolker/broom.mixed")
then ggcoef_model(test) will work.
I am checking a few of my Cox multivariate regression analyses' proportional hazard assumptions using time-dependent co-variates, using the survival package. The question is looking at survival in groups with different ADAMTS13 levels (a type of enzyme).
Could I check if something is wrong with my code itself? It keeps saying Error in tt(TMAdata$ADAMTS13level.f) : could not find function "tt" . Why?
Notably, ADAMTS13level.f is a factor variable.
cox_multivariate_survival_ADAMTS13 <- coxph(Surv(TMAdata$Daysalive, TMAdata$'Dead=1')
~TMAdata$ADAMTS13level.f
+TMAdata$`Age at diagnosis`
+TMAdata$CCIwithoutage
+TMAdata$Gender.f
+TMAdata$`Peak Creatinine`
+TMAdata$DICorcrit.f,
tt(TMAdata$ADAMTS13level.f),
tt = function(x, t, ...)
{mtrx <- model.matrix(~x)[,-1]
mtrx * log(t)})
Thanks- starting with the fundamentals of my actual code or typos- I have tried different permutations to no avail yet.
#Limey was on the right track!
The time-transformed version of ADAMTS13level.f needs to be added to the model, instead of being separated into a separate argument of coxph(...).
The form of coxph call when testing the time-dependent categorical variables is described in How to use the timeSplitter by Max Gordon.
Other helpful documentation:
coxph - fit proportional hazards regression model
cox_multivariate_survival_ADAMTS13 <-
coxph(
Surv(
Daysalive,
'Dead=1'
) ~
ADAMTS13level.f
+ `Age at diagnosis`
+ CCIwithoutage
+ Gender.f
+ `Peak Creatinine`
+ DICorcrit.f
+ tt(ADAMTS13level.f),
tt = function(x, t, ...) {
mtrx <- model.matrix(~x)[,-1]
mtrx * log(t)
},
data = TMAdata
)
p.s. with the original data, there was also a problem because Daysalive included a zero (0) value, which eventually resulted in an 'infinite predictor' error from coxph, probably because tt transformed the data using a log(t). (https://rdrr.io/github/therneau/survival/src/R/coxph.R)
I have discovered some heteroscedasticity in my model that I would like to compensate for with more robust standard errors. I have tried to use the Huber-White robust standard errors from the merDeriv package in R but I beleive these only work for a GLMM with a binomial distribution. Is there a way I could achieve the same thing for a Negative Binomial distribition?
Model:
library(lme4)
model <- glmer.nb(Jobs ~ 1 + Month + Year + (1|Region), data = df)
Huber-White robust standard errors:
library(merDeriv)
bread.glmerMod(model)
Error:
Error in vcov.lmerMod(object, full = full) : estfun.lmerMod() only works for lmer() models.
Thank you for any help!
This looks like a bug in the package, as far as I can tell (the bread.glmerMod function was calling estfun.lmerMod rather than estfun.glmerMod; there's a broader question here about the design of the generic functions, but never mind ...)
You should be able to install a fixed version from my fork via remotes::install_github("bbolker/merDeriv"), then reload the package and try again.
Alternately, download the tarball, change vcov.lmerMod to vcov.glmerMod in the last line of R/bread.glmerMod.R, and re-install the package ...
Try something like this:
library(lme4)
model <- glmer.nb(Jobs ~ 1 + Month + Year + (1|Region), data = df)
cov <- vcovHC(model, type = "HC1", sandwich = T)
se <- sqrt(diag(cov_m1))
(Can't confirm if it works since this there isn't a reproducible example)
I'm trying to build some models using Zero-Inflated Poisson regression using pscl package and after having manipulated the output object which turns to be zeroinfl, I find that doing residuals(fm_zip) is not equal to fm_zip$residuals.
The following is an example of what I'm talking about:
library("pscl")
data("bioChemists", package = "pscl")
fm_zip <- zeroinfl(art ~ . | 1, data = bioChemists)
names(fm_zip)
fm_zip$residuals
residuals(fm_zip)
all.equal(fm_zip$residuals,residuals(fm_zip))
qplot(fm_zip$residuals,residuals(fm_zip))
As you might realize, the results are not equal. I would say that both ways are equivalent but it seems like they're not. Could you explain me what is wrong with this? According to residuals R help, those two alternatives are supposed to return the difference (observed - fitted). By contrast, I did the same with a plain vanilla linear regression and they are equal.
My R version is:
sessionInfo()
R version 3.0.1 (2013-05-16)
Platform: x86_64-w64-mingw32/x64 (64-bit)...
and the package verion is pscl_1.04.4
Any help is appreciated.
To get equal result you should set type to response ( pearson by default)
all.equal(fm_zip$residuals,residuals(fm_zip,'response'))
[1] TRUE
From the ?residuals.zeroinfl:
The residuals method can compute raw residuals (observed - fitted) and
Pearson residuals (raw residuals scaled by square root of variance
function).
The perason variance is defined as:
mu <- predict(fm_zip, type = "count")
phi <- predict(fm_zip, type = "zero")
theta1 <- switch(fm_zip$dist, poisson = 0,
geometric = 1,
negbin = 1/object$theta)
variance <- fm_zip$fitted.values * (1 + (phi + theta1) * mu)
EDIT
Don't hesitate to read the code behind, it is generally a source of learning and you can also avoid many confusions. To get the code behind the S3 method residuals.zeroinfl, you can use something like this :
getS3method('residuals','zeroinfl')