Dear R users:
I am using survreg for modeling left censored longitudinal data. When I am using
the following code for fitting the tobit model I am getting some output with an
warning message(highlighted with red color):
> survreg(Surv(y, y>=0, type='left')~x + frailty(id),
cytokine.data, weight=w, dist='gaussian', scale=1)
Call:
survreg(formula = Surv(y, y >= 0, type = "left") ~ x + frailty(id),
data = cytokine.data, weights = w, dist = "gaussian", scale = 1)
coef se(coef) se2 Chisq DF p
(Intercept) -1.5099 0.3626 0.24322 17.3 1 3.1e-05
x 0.0404 0.0079 0.00493 26.2 1 3.0e-07
frailty(id) 13853.2 1039 0.0e+00
Scale fixed at 1
Iterations: 10 outer, 72 Newton-Raphson
Variance of random effect= 12.1 I-likelihood = -20098.2
Degrees of freedom for terms= 0.5 0.4 1039.4
Likelihood ratio test=232877 on 1039 df, p=0
n=4840 (57 observations deleted due to missingness)
Warning message:
Inner loop failed to coverge for iterations 2 in: survpenal.fit(X, Y, weights,
offset, init = init, controlvals = control, >
Could you please help me in finding the error in my code (if any) so that I will
not get this error message? I would really appreciate if you could help me in
this regard.
Thank you so much.
Sincerely,
Sattar
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