On Aug 12, 2010, at 10:35 AM, asdir wrote:


This command


cdmoutcome<- glm(log(value)~factor(year)
             +log(gdppcpppconst)+log(gdppcpppconstAII)
             +log(co2eemisspc)+log(co2eemisspcAII)
             +log(dist)
             +fdiboth
             +odapartnertohost
             +corrupt
             +log(infraindex)
             +litrate
             +africa
             +imr
                , data=cdmdata2, subset=zero==1, gaussian(link =
"identity"))

results in this table


Coefficients: (1 not defined because of singularities)
                       Estimate Std. Error t value Pr(>|t|)
(Intercept)            1.216e+01  5.771e+01   0.211   0.8332
factor(year)2006      -1.403e+00  5.777e-01  -2.429   0.0157 *
factor(year)2007      -2.799e-01  7.901e-01  -0.354   0.7234
log(gdppcpppconst)     2.762e-01  5.517e+00   0.050   0.9601
log(gdppcpppconstAII) -1.344e-01  9.025e-01  -0.149   0.8817
log(co2eemisspc)       5.655e+00  2.903e+00   1.948   0.0523 .
log(co2eemisspcAII)   -1.411e-01  4.245e-01  -0.332   0.7399
log(dist)             -2.938e-01  4.023e-01  -0.730   0.4658
fdiboth                1.326e-04  1.133e-04   1.171   0.2425
odapartnertohost       2.319e-03  1.437e-03   1.613   0.1078
corrupt                1.875e+00  3.313e+00   0.566   0.5718
log(infraindex)        4.783e+00  1.091e+01   0.438   0.6615

You have probably created litrate as a factor without realizing it. That can easily happen if you just use read.table and one of the values cannot be gracefully interpreted as a numeric. Either read in with stringsAsFactors=FALSE or asIs=TRUE and then coerce it to numeric. or if you want to fix an existing factor f%^&-up, then the FAQ tells you to use something like: cdmdata2$f_ed_variable <- as.numeric(as.character(cdmdata2$f_ed_variable)


litrate0.47           -2.485e+01  3.190e+01  -0.779   0.4365
litrate0.499          -1.657e+01  2.591e+01  -0.639   0.5230
litrate0.523          -2.440e+01  3.427e+01  -0.712   0.4769
litrate0.528          -9.184e+00  1.379e+01  -0.666   0.5060
litrate0.595          -2.309e+01  2.776e+01  -0.832   0.4062
litrate0.66           -1.451e+01  2.734e+01  -0.531   0.5961
litrate0.675          -1.707e+01  2.813e+01  -0.607   0.5444
litrate0.68           -6.346e+00  1.063e+01  -0.597   0.5509
litrate0.699           2.717e+00  3.541e+00   0.768   0.4434
litrate0.706          -1.960e+01  2.933e+01  -0.668   0.5046
litrate0.714          -2.586e+01  4.002e+01  -0.646   0.5186
litrate0.736           5.641e+00  1.561e+01   0.361   0.7181
litrate0.743          -2.692e+01  4.253e+01  -0.633   0.5273
litrate0.762          -2.208e+01  3.100e+01  -0.712   0.4767
litrate0.802          -2.325e+01  3.766e+01  -0.617   0.5375
litrate0.847          -2.620e+01  3.948e+01  -0.664   0.5075
litrate0.86           -3.576e+01  4.950e+01  -0.722   0.4707
litrate0.864          -4.482e+01  6.274e+01  -0.714   0.4755
litrate0.872          -1.946e+01  2.715e+01  -0.717   0.4739
litrate0.877          -2.710e+01  3.702e+01  -0.732   0.4646
litrate0.879          -3.460e+01  5.147e+01  -0.672   0.5020
litrate0.886          -3.276e+01  4.860e+01  -0.674   0.5008
litrate0.889          -4.120e+01  5.755e+01  -0.716   0.4746
litrate0.904          -2.282e+01  2.985e+01  -0.764   0.4453
litrate0.91           -3.478e+01  5.037e+01  -0.691   0.4904
litrate0.923          -1.762e+01  2.551e+01  -0.691   0.4902
litrate0.925          -2.445e+01  3.611e+01  -0.677   0.4990
litrate0.926          -2.995e+01  4.565e+01  -0.656   0.5123
litrate0.928          -2.839e+01  3.933e+01  -0.722   0.4710
litrate0.937          -2.571e+01  3.795e+01  -0.677   0.4986
litrate0.94           -2.109e+01  3.051e+01  -0.691   0.4900
litrate0.959          -2.078e+01  2.895e+01  -0.718   0.4735
litrate0.96           -3.403e+01  4.798e+01  -0.709   0.4787
litrate0.962          -4.084e+01  5.755e+01  -0.710   0.4785
litrate0.971          -3.743e+01  5.247e+01  -0.713   0.4761
litrate0.98           -3.709e+01  5.170e+01  -0.717   0.4737
litrate0.986          -2.663e+01  4.437e+01  -0.600   0.5488
litrate0.991          -3.045e+01  4.166e+01  -0.731   0.4654
litrate1              -2.732e+01  4.459e+01  -0.613   0.5405
africa                        NA         NA      NA       NA
imr                    2.160e+00  9.357e-01   2.309   0.0216 *

although it should result in something similar to this:


Coefficients: (1 not defined because of singularities)
                       Estimate Std. Error t value Pr(>|t|)
(Intercept)            1.216e+01  5.771e+01   0.211   0.8332
factor(year)2006      -1.403e+00  5.777e-01  -2.429   0.0157 *
factor(year)2007      -2.799e-01  7.901e-01  -0.354   0.7234
log(gdppcpppconst)     2.762e-01  5.517e+00   0.050   0.9601
log(gdppcpppconstAII) -1.344e-01  9.025e-01  -0.149   0.8817
log(co2eemisspc)       5.655e+00  2.903e+00   1.948   0.0523 .
log(co2eemisspcAII)   -1.411e-01  4.245e-01  -0.332   0.7399
log(dist)             -2.938e-01  4.023e-01  -0.730   0.4658
fdiboth                1.326e-04  1.133e-04   1.171   0.2425
odapartnertohost       2.319e-03  1.437e-03   1.613   0.1078
corrupt                1.875e+00  3.313e+00   0.566   0.5718
log(infraindex)        4.783e+00  1.091e+01   0.438   0.6615
litrate               -2.485e+01  3.190e+01  -0.779   0.4365
africa             -2.732e+01  4.459e+01  -0.613   0.5405
imr                    2.160e+00  9.357e-01   2.309   0.0216 *

In fact, if I don't use the litrate variable, the regression runs just fine. If I use the variable in a different regression, it also works fine. I just
can't find the point where it turns ugly.

I tested the litrate-variable for everything I know to test for: The
structure is numerical and it does not contain any missings. It has the same length as every other variable in the set and is a continuous variable with
values between 0 and 1.

Does anyone have an idea?
--
View this message in context: 
http://r.789695.n4.nabble.com/Regression-Error-Otherwise-good-variable-causes-singularity-Why-tp2322780p2322780.html
Sent from the R help mailing list archive at Nabble.com.

______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
West Hartford, CT

______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Reply via email to