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. 2021 Apr 29;12:615162. doi: 10.3389/fpsyg.2021.615162

TABLE 4.

Simulation study 1: bias and RMSE for unconstrained maximum likelihood (ML) estimation and constrained maximum likelihood (CML) estimation of the latent correlation as a function of the true correlation (ρ), the sample size (N), and different sets of replications.

Bias
RMSE
Conv+Adm.
Conv.
All Conv+Adm.
Conv.
All
ρ N ML CML ML CML CML ML CML ML CML CML
0.3 30 0.022 0.055 0.043 0.068 –0.016 0.352 0.358 0.395 0.395 0.411
50 0.025 0.035 0.040 0.049 –0.003 0.284 0.288 0.310 0.309 0.328
100 0.003 0.006 0.004 0.006 –0.004 0.202 0.201 0.203 0.203 0.210
0.5 30 –0.037 –0.003 0.019 0.048 –0.025 0.299 0.295 0.332 0.322 0.360
50 –0.042 –0.032 –0.015 –0.005 –0.049 0.266 0.262 0.299 0.285 0.316
100 0.000 0.002 0.006 0.008 0.003 0.196 0.194 0.202 0.201 0.206
0.7 30 0.124 0.088 –0.034 –0.008 0.068 0.299 0.269 0.299 0.274 0.344
50 0.071 0.063 –0.012 –0.005 –0.035 0.242 0.234 0.252 0.245 0.275
100 –0.026 –0.025 –0.004 –0.003 –0.004 0.172 0.171 0.184 0.183 0.185

RMSE = root mean square error; ρ = true latent correlation; N = sample size; ML = unconstrained ML estimation; CML = constrained ML estimation. Conv+Adm = all replications in which unconstrained ML converged with admissible values, that is, estimated correlation was within the interval [−1, 1]; Conv = all replications in which unconstrained ML estimation converged and estimated correlations outside [−1, 1] are truncated to −1 or 1; All = all replications (only constrained ML produced estimates for all replications). Biases smaller than −0.05 or larger than.05 are printed in bold.