Replicating the best loglikelihood PreviousNext
Mplus Discussion > Latent Variable Mixture Modeling >
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 Gareth posted on Saturday, November 13, 2010 - 12:41 pm
Should the best loglikelihood be replicated to two decimal places, or is the nearest whole number sufficient?

For example:

Final stage loglikelihood values at local maxima, seeds, and initial stage start numbers:
-46462.753 514326 325
-46462.754 635245 121
-46462.754 991329 182
-46462.756 227563 63
-46462.757 930323 267
-46462.757 146900 391
...
 Bengt O. Muthen posted on Saturday, November 13, 2010 - 10:01 pm
If this is obtained by numerical integration, you don't need all 3 decimals to agree. When uncertain, use OPTSEED to run contending solutions and see how different the parameter estimates are - often they are essentially the same in these situations.
 John Woo posted on Wednesday, September 16, 2015 - 5:49 pm
Hi Dr. Muthen, I am seeing a rather strange case of log likelihood replication. No matter whether start=100 or start=1000, I see this:
-706.710 846194 93
-708.841 311214 64
-708.841 915107 54
-708.841 354559 73
-708.841 650371 14
-708.841 392418 28
-708.841 804561 59
-708.841 902278 21
-708.841 565819 65
-708.842 207896 25

I am running GMM, and the results associated with the second best LL (-708.841, which is replicated) is very reasonable. But the result associated with the best but non replicated LL (-706.841) has negative residual variances for my growth factors and is problematic. What should I make of this? Why is there always that gap between the best and the second-best no matter the number of random starts? Is there a case where using the second best but replicated LL is acceptable? Thank you in advance.
 Bengt O. Muthen posted on Wednesday, September 16, 2015 - 11:24 pm
An inadmissible estimated model like your first one should be ignored. If a variance is zero the loglikelihood can shoot up.
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