Hi everyone, I have a dataset of plant drought tolerance values, and my original goal was to partition variance in these values among the nested random levels Biome/Study site. However, my drought tolerance data is significantly non-normal, and is best-fit by a gamma distribution, according to the R package fitdistr. Since lme4 doesn't seem to be able to work with gamma distributions (I got the same error as described in this thread: https://stat.ethz.ch/pipermail/r-sig-mixed- models/2010q2/003786.html), I wanted to use zelig to determine which level accounts for the greatest variance in this trait. I tried specifying the following model: zelig(V37 ~ tag(1|Biomes/Site_Numbers), data = Seasonal_sites, model = "gamma.mixed") -> mod1 But I get the following error message: "In mer_finalize(ans) : singular convergence (7)" And my estimated variances go to infinity: 0: 54.614133: 0.263523 2.62573 1: -1594.5787: 0.00000 18.5619 2: -1917.2900: 0.00000 25.9591 3: -2469.0981: 0.0137130 45.6228 4: -2936.0296: 0.00000 73.0933 5: -3428.4451: 0.00000 119.754 6: -3910.9637: 0.000840655 193.870 7: -4510.8977: 0.00000 352.310 8: -4903.5986: 0.00000 520.560 9: -5425.1380: 0.00000 873.876 10: -5896.6090: 6.68957e-09 1395.44 . . . 86: -42758.744: 8.50187e+09 1.05330e+19 87: -43234.416: 1.36270e+10 1.68826e+19 88: -43802.180: 2.39304e+10 2.96476e+19 89: -44250.090: 3.73145e+10 4.62293e+19 Why am I getting this odd result- am I doing something wrong? The drought tolerance data "V37" varies from roughly 1 -6, with n = 185, if that helps. Please let me know if I can supply any more info about my data. Thanks very much for your help!