NOTE: model_summary
is preferred.
Arguments
- model
A model fitted with
lmer
orglmer
function using thelmerTest
package.- test.rand
[Only for
lmer
andglmer
]TRUE
orFALSE
(default). Test random effects (i.e., variance components) by using the likelihood-ratio test (LRT), which is asymptotically chi-square distributed. For large datasets, it is much time-consuming.- digits
Number of decimal places of output. Defaults to
3
.- ...
Other arguments. You may re-define
formula
,data
, orfamily
.
References
Hox, J. J. (2010). Multilevel analysis: Techniques and applications (2nd ed.). New York, NY: Routledge.
Nakagawa, S., & Schielzeth, H. (2013). A general and simple method for obtaining R^2 from generalized linear mixed-effects models. Methods in Ecology and Evolution, 4, 133--142.
Xu, R. (2003). Measuring explained variation in linear mixed effects models. Statistics in Medicine, 22, 3527--3541.
Examples
library(lmerTest)
## Example 1: data from lme4::sleepstudy
# (1) 'Subject' is a grouping/clustering variable
# (2) 'Days' is a level-1 predictor nested within 'Subject'
# (3) No level-2 predictors
m1 = lmer(Reaction ~ (1 | Subject), data=sleepstudy)
m2 = lmer(Reaction ~ Days + (1 | Subject), data=sleepstudy)
m3 = lmer(Reaction ~ Days + (Days | Subject), data=sleepstudy)
HLM_summary(m1)
#>
#> Hierarchical Linear Model (HLM)
#> (also known as) Linear Mixed Model (LMM)
#> (also known as) Multilevel Linear Model (MLM)
#>
#> Model Information:
#> Formula: Reaction ~ (1 | Subject)
#> Level-1 Observations: N = 180
#> Level-2 Groups/Clusters: Subject, 18
#>
#> Model Fit:
#> AIC = 1910.327
#> BIC = 1919.905
#> R_(m)² = 0.00000 (Marginal R²: fixed effects)
#> R_(c)² = 0.39489 (Conditional R²: fixed + random effects)
#> Omega² = 0.43347 (= 1 - proportion of unexplained variance)
#>
#> Fixed Effects:
#> Unstandardized Coefficients (b or γ):
#> Outcome Variable: Reaction
#> ────────────────────────────────────────────────────────────────────
#> b/γ S.E. t df p [95% CI of b/γ]
#> ────────────────────────────────────────────────────────────────────
#> (Intercept) 298.508 (9.050) 32.98 17.0 <.001 *** [279.414, 317.602]
#> ────────────────────────────────────────────────────────────────────
#> 'df' is estimated by Satterthwaite approximation.
#>
#> Random Effects:
#> ────────────────────────────────────────────
#> Cluster K Parameter Variance ICC
#> ────────────────────────────────────────────
#> Subject 18 (Intercept) 1278.33776 0.39489
#> Residual 1958.86518
#> ────────────────────────────────────────────
#>
HLM_summary(m2)
#>
#> Hierarchical Linear Model (HLM)
#> (also known as) Linear Mixed Model (LMM)
#> (also known as) Multilevel Linear Model (MLM)
#>
#> Model Information:
#> Formula: Reaction ~ Days + (1 | Subject)
#> Level-1 Observations: N = 180
#> Level-2 Groups/Clusters: Subject, 18
#>
#> Model Fit:
#> AIC = 1794.465
#> BIC = 1807.237
#> R_(m)² = 0.27989 (Marginal R²: fixed effects)
#> R_(c)² = 0.70426 (Conditional R²: fixed + random effects)
#> Omega² = 0.72586 (= 1 - proportion of unexplained variance)
#>
#> ANOVA Table:
#> ───────────────────────────────────────────────────────
#> Sum Sq Mean Sq NumDF DenDF F p
#> ───────────────────────────────────────────────────────
#> Days 162702.65 162702.65 1.00 161.00 169.40 <.001 ***
#> ───────────────────────────────────────────────────────
#>
#> Fixed Effects:
#> Unstandardized Coefficients (b or γ):
#> Outcome Variable: Reaction
#> ─────────────────────────────────────────────────────────────────────
#> b/γ S.E. t df p [95% CI of b/γ]
#> ─────────────────────────────────────────────────────────────────────
#> (Intercept) 251.405 (9.747) 25.79 22.8 <.001 *** [231.233, 271.577]
#> Days 10.467 (0.804) 13.02 161.0 <.001 *** [ 8.879, 12.055]
#> ─────────────────────────────────────────────────────────────────────
#> 'df' is estimated by Satterthwaite approximation.
#>
#> Standardized Coefficients (β):
#> Outcome Variable: Reaction
#> ────────────────────────────────────────────────────────
#> β S.E. t df p [95% CI of β]
#> ────────────────────────────────────────────────────────
#> Days 0.535 (0.041) 13.02 161.0 <.001 *** [0.454, 0.616]
#> ────────────────────────────────────────────────────────
#>
#> Random Effects:
#> ────────────────────────────────────────────
#> Cluster K Parameter Variance ICC
#> ────────────────────────────────────────────
#> Subject 18 (Intercept) 1378.17851 0.58931
#> Residual 960.45658
#> ────────────────────────────────────────────
#>
HLM_summary(m3)
#>
#> Hierarchical Linear Model (HLM)
#> (also known as) Linear Mixed Model (LMM)
#> (also known as) Multilevel Linear Model (MLM)
#>
#> Model Information:
#> Formula: Reaction ~ Days + (Days | Subject)
#> Level-1 Observations: N = 180
#> Level-2 Groups/Clusters: Subject, 18
#>
#> Model Fit:
#> AIC = 1755.628
#> BIC = 1774.786
#> R_(m)² = 0.27865 (Marginal R²: fixed effects)
#> R_(c)² = 0.79922 (Conditional R²: fixed + random effects)
#> Omega² = 0.82590 (= 1 - proportion of unexplained variance)
#>
#> ANOVA Table:
#> ───────────────────────────────────────────────────
#> Sum Sq Mean Sq NumDF DenDF F p
#> ───────────────────────────────────────────────────
#> Days 30030.94 30030.94 1.00 17.00 45.85 <.001 ***
#> ───────────────────────────────────────────────────
#>
#> Fixed Effects:
#> Unstandardized Coefficients (b or γ):
#> Outcome Variable: Reaction
#> ────────────────────────────────────────────────────────────────────
#> b/γ S.E. t df p [95% CI of b/γ]
#> ────────────────────────────────────────────────────────────────────
#> (Intercept) 251.405 (6.825) 36.84 17.0 <.001 *** [237.006, 265.804]
#> Days 10.467 (1.546) 6.77 17.0 <.001 *** [ 7.206, 13.729]
#> ────────────────────────────────────────────────────────────────────
#> 'df' is estimated by Satterthwaite approximation.
#>
#> Standardized Coefficients (β):
#> Outcome Variable: Reaction
#> ──────────────────────────────────────────────────────
#> β S.E. t df p [95% CI of β]
#> ──────────────────────────────────────────────────────
#> Days 0.535 (0.079) 6.77 17.0 <.001 *** [0.368, 0.702]
#> ──────────────────────────────────────────────────────
#>
#> Random Effects:
#> ───────────────────────────────────────────
#> Cluster K Parameter Variance ICC
#> ───────────────────────────────────────────
#> Subject 18 (Intercept) 612.10016 0.48309
#> Days 35.07171
#> Residual 654.94001
#> ───────────────────────────────────────────
#>
## Example 2: data from lmerTest::carrots
# (1) 'Consumer' is a grouping/clustering variable
# (2) 'Sweetness' is a level-1 predictor
# (3) 'Age' and 'Frequency' are level-2 predictors
hlm.1 = lmer(Preference ~ Sweetness + Age + Frequency +
(1 | Consumer), data=carrots)
hlm.2 = lmer(Preference ~ Sweetness + Age + Frequency +
(Sweetness | Consumer) + (1 | Product), data=carrots)
HLM_summary(hlm.1)
#>
#> Hierarchical Linear Model (HLM)
#> (also known as) Linear Mixed Model (LMM)
#> (also known as) Multilevel Linear Model (MLM)
#>
#> Model Information:
#> Formula: Preference ~ Sweetness + Age + Frequency + (1 | Consumer)
#> Level-1 Observations: N = 1230
#> Level-2 Groups/Clusters: Consumer, 103
#>
#> Model Fit:
#> AIC = 3328.442
#> BIC = 3384.705
#> R_(m)² = 0.32908 (Marginal R²: fixed effects)
#> R_(c)² = 0.52156 (Conditional R²: fixed + random effects)
#> Omega² = 0.50163 (= 1 - proportion of unexplained variance)
#>
#> ANOVA Table:
#> ────────────────────────────────────────────────────────
#> Sum Sq Mean Sq NumDF DenDF F p
#> ────────────────────────────────────────────────────────
#> Sweetness 487.13 487.13 1.00 1208.87 660.42 <.001 ***
#> Age 4.11 1.37 3.00 93.39 1.86 .142
#> Frequency 1.80 0.45 4.00 93.75 0.61 .655
#> ────────────────────────────────────────────────────────
#>
#> Fixed Effects:
#> Unstandardized Coefficients (b or γ):
#> Outcome Variable: Preference
#> ──────────────────────────────────────────────────────────────────
#> b/γ S.E. t df p [95% CI of b/γ]
#> ──────────────────────────────────────────────────────────────────
#> (Intercept) 2.626 (0.220) 11.93 119.9 <.001 *** [ 2.190, 3.061]
#> Sweetness 0.508 (0.020) 25.70 1208.9 <.001 *** [ 0.469, 0.547]
#> Age2 0.395 (0.249) 1.58 93.6 .117 [-0.100, 0.890]
#> Age3 0.465 (0.214) 2.17 93.7 .033 * [ 0.039, 0.891]
#> Age4 0.531 (0.234) 2.27 93.6 .026 * [ 0.066, 0.996]
#> Frequency2 0.149 (0.162) 0.92 93.4 .360 [-0.172, 0.469]
#> Frequency3 0.101 (0.217) 0.47 93.6 .642 [-0.330, 0.532]
#> Frequency4 -0.501 (0.444) -1.13 93.2 .262 [-1.382, 0.380]
#> Frequency5 -0.027 (0.376) -0.07 94.7 .943 [-0.774, 0.720]
#> ──────────────────────────────────────────────────────────────────
#> 'df' is estimated by Satterthwaite approximation.
#>
#> Standardized Coefficients (β):
#> Outcome Variable: Preference
#> ─────────────────────────────────────────────────────────────────
#> β S.E. t df p [95% CI of β]
#> ─────────────────────────────────────────────────────────────────
#> Sweetness 0.609 (0.024) 25.70 1208.9 <.001 *** [ 0.562, 0.655]
#> Age2 0.122 (0.077) 1.58 93.6 .117 [-0.031, 0.275]
#> Age3 0.198 (0.091) 2.17 93.7 .033 * [ 0.017, 0.380]
#> Age4 0.197 (0.087) 2.27 93.6 .026 * [ 0.025, 0.369]
#> Frequency2 0.047 (0.051) 0.92 93.4 .360 [-0.055, 0.149]
#> Frequency3 0.024 (0.052) 0.47 93.6 .642 [-0.080, 0.129]
#> Frequency4 -0.059 (0.052) -1.13 93.2 .262 [-0.163, 0.045]
#> Frequency5 -0.004 (0.053) -0.07 94.7 .943 [-0.108, 0.101]
#> ─────────────────────────────────────────────────────────────────
#>
#> Random Effects:
#> ──────────────────────────────────────────
#> Cluster K Parameter Variance ICC
#> ──────────────────────────────────────────
#> Consumer 103 (Intercept) 0.29673 0.28688
#> Residual 0.73761
#> ──────────────────────────────────────────
#>
HLM_summary(hlm.2)
#>
#> Hierarchical Linear Model (HLM)
#> (also known as) Linear Mixed Model (LMM)
#> (also known as) Multilevel Linear Model (MLM)
#>
#> Model Information:
#> Formula: Preference ~ Sweetness + Age + Frequency + (Sweetness | Consumer) + (1 | Product)
#> Level-1 Observations: N = 1230
#> Level-2 Groups/Clusters: Consumer, 103; Product, 12
#>
#> Model Fit:
#> AIC = 3281.886
#> BIC = 3353.493
#> R_(m)² = 0.31128 (Marginal R²: fixed effects)
#> R_(c)² = 0.55254 (Conditional R²: fixed + random effects)
#> Omega² = 0.57170 (= 1 - proportion of unexplained variance)
#>
#> ANOVA Table:
#> ───────────────────────────────────────────────────────
#> Sum Sq Mean Sq NumDF DenDF F p
#> ───────────────────────────────────────────────────────
#> Sweetness 184.22 184.22 1.00 103.72 277.74 <.001 ***
#> Age 2.51 0.84 3.00 83.12 1.26 .293
#> Frequency 2.43 0.61 4.00 80.03 0.92 .458
#> ───────────────────────────────────────────────────────
#>
#> Fixed Effects:
#> Unstandardized Coefficients (b or γ):
#> Outcome Variable: Preference
#> ─────────────────────────────────────────────────────────────────
#> b/γ S.E. t df p [95% CI of b/γ]
#> ─────────────────────────────────────────────────────────────────
#> (Intercept) 2.817 (0.221) 12.76 149.7 <.001 *** [ 2.381, 3.253]
#> Sweetness 0.485 (0.029) 16.67 103.7 <.001 *** [ 0.428, 0.543]
#> Age2 0.212 (0.222) 0.96 78.6 .341 [-0.229, 0.654]
#> Age3 0.297 (0.189) 1.57 76.3 .120 [-0.080, 0.674]
#> Age4 0.388 (0.207) 1.87 77.6 .065 . [-0.025, 0.801]
#> Frequency2 0.181 (0.150) 1.21 92.9 .230 [-0.117, 0.479]
#> Frequency3 0.095 (0.203) 0.47 96.4 .639 [-0.307, 0.497]
#> Frequency4 -0.516 (0.383) -1.35 68.4 .183 [-1.281, 0.249]
#> Frequency5 -0.055 (0.327) -0.17 70.4 .867 [-0.707, 0.597]
#> ─────────────────────────────────────────────────────────────────
#> 'df' is estimated by Satterthwaite approximation.
#>
#> Standardized Coefficients (β):
#> Outcome Variable: Preference
#> ────────────────────────────────────────────────────────────────
#> β S.E. t df p [95% CI of β]
#> ────────────────────────────────────────────────────────────────
#> Sweetness 0.581 (0.035) 16.67 103.7 <.001 *** [ 0.512, 0.650]
#> Age2 0.066 (0.069) 0.96 78.6 .341 [-0.071, 0.202]
#> Age3 0.127 (0.081) 1.57 76.3 .120 [-0.034, 0.287]
#> Age4 0.144 (0.077) 1.87 77.6 .065 . [-0.009, 0.297]
#> Frequency2 0.058 (0.048) 1.21 92.9 .230 [-0.037, 0.152]
#> Frequency3 0.023 (0.049) 0.47 96.4 .639 [-0.074, 0.120]
#> Frequency4 -0.061 (0.045) -1.35 68.4 .183 [-0.151, 0.029]
#> Frequency5 -0.008 (0.046) -0.17 70.4 .867 [-0.099, 0.083]
#> ────────────────────────────────────────────────────────────────
#>
#> Random Effects:
#> ──────────────────────────────────────────
#> Cluster K Parameter Variance ICC
#> ──────────────────────────────────────────
#> Consumer 103 (Intercept) 1.11977 0.62512
#> Sweetness 0.04438
#> Product 12 (Intercept) 0.00825 0.00460
#> Residual 0.66328
#> ──────────────────────────────────────────
#>