[R] problems with too many NA in the function ideal() from pscl package.

[Antonio P. Ramos]

Hi all,

I'm trying to run some monte carlo simulation for my roll call data
using the ideal() function, which resides in the pscl package.
However, I'm receiving an error message that I don't understand.

Error in ideal(a, maxiter = 1000, thin = 10, burnin = 50, store.item = TRUE,  :
  NA/NaN/Inf in foreign function call (arg 13)


my code is simple the following:


> m_a <- ideal(a, maxiter = 1000, thin = 10, burnin = 50,
+ 			   store.item = TRUE,  normalize=T,
+ 				priors=list(xp=1e-12,xpv=1e-12,bp=1e-12,bpv=1e-12), verbose=T)
ideal: analysis of roll call data via Markov chain Monte Carlo methods.

Subsetting rollcall object a using dropList
Using the following codes to represent roll call votes:
Yea:		 1
Nay:		 0
Abstentions:	 NA
Not In Legislature:	 9

Ideal Point Estimation

Number of Legislators		 30
Number of Items			 1172

checking for any user-supplied priors...

checking start values...
will use eigen-decomposition method to get start values for ideal points...done
running 1172 vote-specific probit GLMs
 for start values for item/bill parameters
 conditional on start values for ideal points...done
using the following start values for ideal points (summary follows):
       V1
 Min.   :-0.7573
 1st Qu.:-0.1583
 Median : 0.0000
 Mean   :-0.0342
 3rd Qu.: 0.0000
 Max.   : 0.8160
using the following start values for item parameters (summary follows):
       V1                  V2
 Min.   :-131.2397   Min.   :-49.27293
 1st Qu.:  -1.9090   1st Qu.: -1.33518
 Median :  -1.5156   Median : -0.34876
 Mean   :   0.5443   Mean   : -0.07001
 3rd Qu.:   1.6978   3rd Qu.:  1.22064
 Max.   : 553.5285   Max.   : 65.19820
 NA's   : 573.0000

Starting MCMC Iterations...
Error in ideal(a, maxiter = 1000, thin = 10, burnin = 50, store.item = TRUE,  :
  NA/NaN/Inf in foreign function call (arg 13)
+


The problem, I think, is that many data matrix has too many NA. Does
anybody have any suggestion?

Thanks in advance,

Antonio.