Message/Author 


I've got a question concerning the degrees of freedom in a twolevelanalysis. I'm conducting a 2LevelCFA, incorporating 6 variables and two correlated factors on each level. The output indicates that there are 32 free parameters in the model (I agree to that number). With 6 observed continous variables, how many degrees of freedom does the model have (6*732=10?)? According to the MPlusinformation in the chisquare test of model fit section I should have 16 degrees of freedom. Where do those 6 dfs stem from or where am I wrong? Thank you for an explanation. Regards, Florian Fiedler. 

bmuthen posted on Wednesday, June 08, 2005  7:01 am



You should count the 6 means as well  because you work with multivariate normality, the H1 model has 6 means and 2x21 varcovar parameters. 

Sylvie Mrug posted on Thursday, August 02, 2007  12:54 pm



I am running a TWOLEVEL model with 3 Level 2 predictors and 1 Level 1 covariate. How can I determine the df for the ttest of each Level 2 predictor? There are 27 Level 2 clusters. Thanks so much for your help. 


The ratio of the parameter estimate to the standard error (column three of the output) is a zscore. You can compare it to 1.96 for example. 

Sarah Hall posted on Wednesday, December 14, 2011  9:30 pm



Hello, I am using TYPE=TWOLEVEL RANDOM to model relationships between 1 individuallevel predictor and 2 grouplevel predictors and a continuous individuallevel outcome. I need to report the degrees of freedom for each of the effects, but I notice that these are not provided in the Mplus output. What is the formula for calculating degrees of freedom in a multilevel model such as the one I've described? Thank you! Sarah 


In a model where means, variances, and covariances are not sufficient statistics for model estimation, degrees of freedom for the chisquare test are not relevant. 

Sarah Hall posted on Friday, December 16, 2011  12:08 am



Sorry I should have specified  I am actually trying to obtain the degrees of freedom for the ttests for each of my effects. 


The test we give is a ztest in large samples and does not use degrees of freedom. 

Kätlin Peets posted on Saturday, February 01, 2014  2:00 am



Hi, I am also being told that degrees of freedom should be included in statistics reported in text. I have twolevel models where I test interactions between two contextual variables (thus, interactions are at Level 2). I report results for my simple slopes (at high and low values of the moderator) in the text. What is the correct way to calculate degrees of freedom for my simple slopes? Is it N (number of level2 units)  number of level2 variables in the model? Thank you! 


The ratio of the parameter estimate to its standard error is a ztest in large samples. There are no degrees of freedom involved with ztests. Degrees of freedom are involved with ttests which Mplus does not give. 

Amy Walzer posted on Tuesday, February 11, 2014  4:31 pm



In reading the previous posts I see that a ztest is used to test significance in large samples. However, I am doing a twolevel model with 2 individuallevel predictors and 1 grouplevel predictor. I have 126 participants among 11 groups. Can this be considered a large sample? Thank you, Amy 


If you have 11 clusters, this is not enough for multilevel modeling. You should create 10 dummy variables and use them as covariates to control for nonindependence of observations. In this case, 126 should be enough. 

Back to top 