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We generate data using the CULTA model with two latent profiles, where profile membership depends on a covariate and profile transitions follow a multinomial structure. However, for model fitting, we impose a simpler structure by fitting a CUTS (1 Profile) model with autoregressive effects, ignoring the latent profiles during estimation. We then compare this misspecified model to the correctly specified two-profile CULTA model.

Data Generation

# complete list of R function arguments

# random seed for reproducibility
set.seed(42)

# dimensions
n # number of individuals
#> [1] 200
m # measurement occasions
#> [1] 6
p # number of items
#> [1] 4
q # common trait dimension
#> [1] 1

# covariate parameters
mu_x 
#> [1] 0
sigma_x
#> [1] 1

# profile membership and transition parameters
nu_0
#> [1] -0.405
kappa_0
#> [1] 0.1
alpha_0
#> [1] -0.5
beta_00
#> [1] 0.85
gamma_00
#> [1] 0.2
gamma_10
#> [1] 0.2

# trait parameters
psi_t
#>      [,1]
#> [1,]  0.3
mu_t
#> [1] 0
psi_p
#>      [,1] [,2] [,3] [,4]
#> [1,]  0.3  0.0  0.0  0.0
#> [2,]  0.0  0.3  0.0  0.0
#> [3,]  0.0  0.0  0.3  0.0
#> [4,]  0.0  0.0  0.0  0.3
mu_p
#> [1] 0 0 0 0
common_trait_loading
#>      [,1]
#> [1,]    1
#> [2,]    1
#> [3,]    1
#> [4,]    1

# state parameters
common_state_loading
#>      [,1]
#> [1,]    1
#> [2,]    1
#> [3,]    1
#> [4,]    1
phi_0
#> [1] 0
phi_1
#> [1] 0.311
psi_s0
#> [1] 1
psi_s
#> [1] 0.5
theta
#>      [,1] [,2] [,3] [,4]
#> [1,]  0.2  0.0  0.0  0.0
#> [2,]  0.0  0.2  0.0  0.0
#> [3,]  0.0  0.0  0.2  0.0
#> [4,]  0.0  0.0  0.0  0.2

# profile-specific means
mu_profile
#>       [,1]   [,2]
#> [1,] 2.253 -0.278
#> [2,] 1.493 -0.165
#> [3,] 1.574 -0.199
#> [4,] 1.117 -0.148
data <- GenCULTA2Profiles(
  n = n,
  m = m,
  mu_x = mu_x,
  sigma_x = sigma_x,
  nu_0 = nu_0,
  kappa_0 = kappa_0,
  alpha_0 = alpha_0,
  beta_00 = beta_00,
  gamma_00 = gamma_00,
  gamma_10 = gamma_10,
  mu_t = mu_t,
  psi_t = psi_t,
  mu_p = mu_p,
  psi_p = psi_p,
  common_trait_loading = common_trait_loading,
  common_state_loading = common_state_loading,
  phi_0 = phi_0,
  phi_1 = phi_1,
  psi_s0 = psi_s0,
  psi_s = psi_s,
  theta = theta, 
  mu_profile = mu_profile
)

Model Fitting

The FitCULTA1Profiles function fits the misspecified one-profile model using Mplus. Note: This function requires that Mplus is already installed on the system.

one_profile <- FitCULTA1Profile(data = data)
summary(one_profile)
#>              est     se       z      p   2.5%  97.5%
#> mu_1      0.8760 0.0756 11.5939 0.0000 0.7279 1.0241
#> mu_2      0.6893 0.0680 10.1375 0.0000 0.5561 0.8226
#> mu_3      0.6653 0.0693  9.5992 0.0000 0.5295 0.8011
#> mu_4      0.5206 0.0616  8.4480 0.0000 0.3999 0.6414
#> lambda_t2 0.9405 0.1094  8.5960 0.0000 0.7260 1.1549
#> lambda_s2 0.7756 0.0146 53.0696 0.0000 0.7470 0.8043
#> lambda_t3 0.9325 0.1525  6.1158 0.0000 0.6337 1.2314
#> lambda_s3 0.8070 0.0145 55.5545 0.0000 0.7785 0.8355
#> lambda_t4 0.7139 0.1305  5.4709 0.0000 0.4582 0.9697
#> lambda_s4 0.6782 0.0137 49.4419 0.0000 0.6513 0.7051
#> theta_11  0.2968 0.0198 14.9955 0.0000 0.2580 0.3356
#> theta_22  0.2219 0.0125 17.6984 0.0000 0.1973 0.2465
#> theta_33  0.1966 0.0126 15.6618 0.0000 0.1720 0.2212
#> theta_44  0.2273 0.0112 20.3052 0.0000 0.2054 0.2493
#> phi       0.2302 0.0430  5.3475 0.0000 0.1458 0.3145
#> psi_t     0.3828 0.1265  3.0269 0.0025 0.1349 0.6306
#> psi_p_11  0.2208 0.0479  4.6083 0.0000 0.1269 0.3147
#> psi_p_22  0.2495 0.0383  6.5065 0.0000 0.1743 0.3246
#> psi_p_33  0.2732 0.0501  5.4483 0.0000 0.1749 0.3714
#> psi_p_44  0.3006 0.0451  6.6618 0.0000 0.2122 0.3891
#> psi_s0    2.9677 0.2988  9.9310 0.0000 2.3820 3.5534
#> psi_s     1.8330 0.0883 20.7648 0.0000 1.6600 2.0060

The FitCULTA2Profiles function fits the correct two-profile model using Mplus. Note: This function requires that Mplus is already installed on the system. To speed up model fitting, consider using the ncores argument to leverage multiple cores.

two_profiles <- FitCULTA2Profiles(data = data)
summary(two_profiles)
#>               est     se       z      p    2.5%   97.5%
#> mu_10      2.1695 0.0815 26.6118 0.0000  2.0097  2.3293
#> mu_20      1.5565 0.0779 19.9824 0.0000  1.4039  1.7092
#> mu_30      1.5795 0.0750 21.0706 0.0000  1.4326  1.7264
#> mu_40      1.1605 0.0698 16.6377 0.0000  1.0238  1.2972
#> lambda_t2  0.9352 0.0958  9.7663 0.0000  0.7475  1.1229
#> lambda_s2  0.9350 0.0408 22.9064 0.0000  0.8550  1.0150
#> lambda_t3  0.9094 0.1310  6.9413 0.0000  0.6526  1.1662
#> lambda_s3  0.9566 0.0459 20.8264 0.0000  0.8666  1.0466
#> lambda_t4  0.6841 0.1047  6.5324 0.0000  0.4788  0.8893
#> lambda_s4  1.0039 0.0452 22.1997 0.0000  0.9152  1.0925
#> theta_11   0.2217 0.0173 12.8371 0.0000  0.1878  0.2555
#> theta_22   0.2296 0.0122 18.8169 0.0000  0.2057  0.2535
#> theta_33   0.2072 0.0124 16.7196 0.0000  0.1829  0.2315
#> theta_44   0.1752 0.0178  9.8294 0.0000  0.1403  0.2101
#> phi_0     -0.0100 0.0669 -0.1489 0.8817 -0.1411  0.1212
#> psi_t      0.4327 0.1040  4.1612 0.0000  0.2289  0.6365
#> psi_p_11   0.2222 0.0485  4.5845 0.0000  0.1272  0.3172
#> psi_p_22   0.2469 0.0382  6.4665 0.0000  0.1721  0.3218
#> psi_p_33   0.2741 0.0500  5.4859 0.0000  0.1762  0.3720
#> psi_p_44   0.3041 0.0450  6.7518 0.0000  0.2158  0.3924
#> psi_s0     1.1566 0.2344  4.9337 0.0000  0.6971  1.6160
#> psi_s      0.4781 0.0639  7.4873 0.0000  0.3530  0.6033
#> mu_11     -0.2859 0.0898 -3.1853 0.0014 -0.4619 -0.1100
#> mu_21     -0.0881 0.0757 -1.1634 0.2447 -0.2365  0.0603
#> mu_31     -0.1545 0.0771 -2.0043 0.0450 -0.3056 -0.0034
#> mu_41     -0.0511 0.0758 -0.6742 0.5002 -0.1996  0.0974
#> phi_1      0.3327 0.0676  4.9230 0.0000  0.2002  0.4651
#> nu_0      -0.2154 0.1909 -1.1283 0.2592 -0.5896  0.1588
#> alpha_0   -0.3451 0.1259 -2.7405 0.0061 -0.5920 -0.0983
#> kappa_0    0.3926 0.2298  1.7083 0.0876 -0.0578  0.8431
#> beta_00    0.6690 0.1680  3.9811 0.0001  0.3396  0.9983
#> gamma_00   0.2315 0.1087  2.1308 0.0331  0.0186  0.4445
#> gamma_10   0.2816 0.1137  2.4768 0.0133  0.0588  0.5044

Model Comparison

The anova function can be used to compare the two fitted models.

anova(one_profile, two_profiles)
#> $fit
#>                    logLik df correction      AIC      BIC     aBIC   entropy
#> 1-profile CULTA -5906.207 22  0.9762563 11856.41 11928.98 11859.28 0.0000000
#> 2-profile CULTA -5850.928 33  1.0236706 11767.86 11876.70 11772.15 0.7169988
#> 
#> $test
#>     chi_diff      df_diff      p_value 
#> 9.884388e+01 1.100000e+01 3.024432e-16

Mplus Script Used

The one-profile model was estimated using the following Mplus script.

TITLE:
  CUTS with AR;

DATA:
  FILE = cutsar_data.dat;

VARIABLE:
  NAMES =
    id
    x
    y1t0
    y2t0
    y3t0
    y4t0
    y1t1
    y2t1
    y3t1
    y4t1
    y1t2
    y2t2
    y3t2
    y4t2
    y1t3
    y2t3
    y3t3
    y4t3
    y1t4
    y2t4
    y3t4
    y4t4
    y1t5
    y2t5
    y3t5
    y4t5
  ;
  USEVARIABLES =
    y1t0
    y2t0
    y3t0
    y4t0
    y1t1
    y2t1
    y3t1
    y4t1
    y1t2
    y2t2
    y3t2
    y4t2
    y1t3
    y2t3
    y3t3
    y4t3
    y1t4
    y2t4
    y3t4
    y4t4
    y1t5
    y2t5
    y3t5
    y4t5
  ;

ANALYSIS:
  TYPE = GENERAL;
  ESTIMATOR = MLR;
  STARTS = 1000;
  MODEL = NOCOV;

MODEL:
  ! common trait ------------------------------------------------------

  !! factor loadings
  !!! t = 0
  t BY y1t0@1;
  t BY y2t0 (lambdat2);
  t BY y3t0 (lambdat3);
  t BY y4t0 (lambdat4);
  !!! t = 1
  t BY y1t1@1;
  t BY y2t1 (lambdat2);
  t BY y3t1 (lambdat3);
  t BY y4t1 (lambdat4);
  !!! t = 2
  t BY y1t2@1;
  t BY y2t2 (lambdat2);
  t BY y3t2 (lambdat3);
  t BY y4t2 (lambdat4);
  !!! t = 3
  t BY y1t3@1;
  t BY y2t3 (lambdat2);
  t BY y3t3 (lambdat3);
  t BY y4t3 (lambdat4);
  !!! t = 4
  t BY y1t4@1;
  t BY y2t4 (lambdat2);
  t BY y3t4 (lambdat3);
  t BY y4t4 (lambdat4);
  !!! t = 5
  t BY y1t5@1;
  t BY y2t5 (lambdat2);
  t BY y3t5 (lambdat3);
  t BY y4t5 (lambdat4);

  !! latent mean
  [ t@0 ];

  !! latent variance
  t (psit);

  ! unique traits -----------------------------------------------------

  !! factor loadings
  !!! k = 1
  u1 BY y1t0@1;
  u1 BY y1t1@1;
  u1 BY y1t2@1;
  u1 BY y1t3@1;
  u1 BY y1t4@1;
  u1 BY y1t5@1;
  !!! k = 2
  u2 BY y2t0@1;
  u2 BY y2t1@1;
  u2 BY y2t2@1;
  u2 BY y2t3@1;
  u2 BY y2t4@1;
  u2 BY y2t5@1;
  !!! k = 3
  u3 BY y3t0@1;
  u3 BY y3t1@1;
  u3 BY y3t2@1;
  u3 BY y3t3@1;
  u3 BY y3t4@1;
  u3 BY y3t5@1;
  !!! k = 4
  u4 BY y4t0@1;
  u4 BY y4t1@1;
  u4 BY y4t2@1;
  u4 BY y4t3@1;
  u4 BY y4t4@1;
  u4 BY y4t5@1;

  !! latent means
  [ u1@0 ];
  [ u2@0 ];
  [ u3@0 ];
  [ u4@0 ];

  !! latent variances
  u1 (psip1);
  u2 (psip2);
  u3 (psip3);
  u4 (psip4);

  ! common states -----------------------------------------------------

  !! factor loadings
  !!! t = 0
  s0 BY y1t0@1;
  s0 BY y2t0 (lambdas2);
  s0 BY y3t0 (lambdas3);
  s0 BY y4t0 (lambdas4);
  !!! t = 1
  s1 BY y1t1@1;
  s1 BY y2t1 (lambdas2);
  s1 BY y3t1 (lambdas3);
  s1 BY y4t1 (lambdas4);
  !!! t = 2
  s2 BY y1t2@1;
  s2 BY y2t2 (lambdas2);
  s2 BY y3t2 (lambdas3);
  s2 BY y4t2 (lambdas4);
  !!! t = 3
  s3 BY y1t3@1;
  s3 BY y2t3 (lambdas2);
  s3 BY y3t3 (lambdas3);
  s3 BY y4t3 (lambdas4);
  !!! t = 4
  s4 BY y1t4@1;
  s4 BY y2t4 (lambdas2);
  s4 BY y3t4 (lambdas3);
  s4 BY y4t4 (lambdas4);
  !!! t = 5
  s5 BY y1t5@1;
  s5 BY y2t5 (lambdas2);
  s5 BY y3t5 (lambdas3);
  s5 BY y4t5 (lambdas4);

  !! latent means
  [ s0@0 ];
  [ s1@0 ];
  [ s2@0 ];
  [ s3@0 ];
  [ s4@0 ];
  [ s5@0 ];

  !! latent variance of s0
  s0 (psis0);

  !! variance of the process noise
  s1 (psis);
  s2 (psis);
  s3 (psis);
  s4 (psis);
  s5 (psis);

  ! unique states -----------------------------------------------------

  !! variances
  !!! t = 0
  y1t0 (theta11);
  y2t0 (theta22);
  y3t0 (theta33);
  y4t0 (theta44);
  !!! t = 1
  y1t1 (theta11);
  y2t1 (theta22);
  y3t1 (theta33);
  y4t1 (theta44);
  !!! t = 2
  y1t2 (theta11);
  y2t2 (theta22);
  y3t2 (theta33);
  y4t2 (theta44);
  !!! t = 3
  y1t3 (theta11);
  y2t3 (theta22);
  y3t3 (theta33);
  y4t3 (theta44);
  !!! t = 4
  y1t4 (theta11);
  y2t4 (theta22);
  y3t4 (theta33);
  y4t4 (theta44);
  !!! t = 5
  y1t5 (theta11);
  y2t5 (theta22);
  y3t5 (theta33);
  y4t5 (theta44);

  ! grand means -------------------------------------------------------

  !! t = 0
  [ y1t0 ] (mu1);
  [ y2t0 ] (mu2);
  [ y3t0 ] (mu3);
  [ y4t0 ] (mu4);
  !! t = 1
  [ y1t1 ] (mu1);
  [ y2t1 ] (mu2);
  [ y3t1 ] (mu3);
  [ y4t1 ] (mu4);
  !! t = 2
  [ y1t2 ] (mu1);
  [ y2t2 ] (mu2);
  [ y3t2 ] (mu3);
  [ y4t2 ] (mu4);
  !! t = 3
  [ y1t3 ] (mu1);
  [ y2t3 ] (mu2);
  [ y3t3 ] (mu3);
  [ y4t3 ] (mu4);
  !! t = 4
  [ y1t4 ] (mu1);
  [ y2t4 ] (mu2);
  [ y3t4 ] (mu3);
  [ y4t4 ] (mu4);
  !! t = 5
  [ y1t5 ] (mu1);
  [ y2t5 ] (mu2);
  [ y3t5 ] (mu3);
  [ y4t5 ] (mu4);

  ! inertia -----------------------------------------------------------

  s0 ON s1 (phi);
  s1 ON s2 (phi);
  s2 ON s3 (phi);
  s3 ON s4 (phi);
  s4 ON s5 (phi);

MODEL CONSTRAINT:
  ! variance constraints
  psit > 0;
  psip1 > 0;
  psip2 > 0;
  psip3 > 0;
  psip4 > 0;
  psis0 > 0;
  psis > 0;
  theta11 > 0;
  theta22 > 0;
  theta33 > 0;
  theta44 > 0;

OUTPUT:
  TECH1
  TECH3
  TECH4;

SAVEDATA:
  ESTIMATES = cutsar_whrNjgvsUbGDkMFGuTSq_estimates.dat;
  RESULTS = cutsar_whrNjgvsUbGDkMFGuTSq_results.dat;
  TECH3 = cutsar_whrNjgvsUbGDkMFGuTSq_tech3.dat;
  TECH4 = cutsar_whrNjgvsUbGDkMFGuTSq_tech4.dat;