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. 2016 Jun 24;42(2):220–231. doi: 10.1093/jpepsy/jsw057

Table III.

Piecewise Linear Mixed Effects Modeling With Random Intercept

  Randomization Intercept
 Slope 1
 Slope 2
Cognitive Outcome Estimate SE p-value* Estimate SE p-value* Estimate SE p-value*
WISC-IV–Digit Span Forwarda Control 8.10 0.54 <.001 0.08 0.05 .080 −0.00 0.02 .828
Intervention 9.00 0.56 .081 0.09 0.05 .061 0.01 0.02 .545
Difference 0.90 0.78 .253 0.01 0.07 .897 0.02 0.03 .561
WISC-IV–Digit Span Backwarda Control 8.58 0.52 .009 0.06 0.05 .247 0.01 0.02 .777
Intervention 8.97 0.54 .062 0.22 0.06 <.001 −0.02 0.02 .256
Difference 0.38 0.75 .611 0.16 0.08 .043 −0.03 0.03 .315
WISC-IV–Letter-Number Sequencinga Control 9.31 0.45 .133 0.06 0.04 .126 −0.01 0.01 .538
Intervention 9.87 0.47 .779 0.15 0.04 <.001 −0.01 0.01 .597
Difference 0.55 0.65 .399 0.09 0.05 .088 0.00 0.02 .948
WISC-IV–Working Memory Indexb Control 91.89 2.38 .001 0.40 0.15 .009 −0.04 0.06 .554
Intervention 95.33 2.51 .067 0.92 0.15 <.001 −0.04 0.06 .463
Difference 3.44 3.46 .322 0.52 0.21 .017 −0.01 0.08 .923
WISC-IV–Spatial Span Forwarda Control 8.56 0.55 .010 0.12 0.06 .030 0.01 0.02 .786
Intervention 9.83 0.57 .770 0.33 0.06 <.001 −0.06 0.02 .012
Difference 1.28 0.79 .107 0.21 0.08 .014 −0.06 0.03 .049
WISC-IV–Spatial Span Backwarda,c Control 10.04 0.49 .940 0.08 0.05 .133 0.00 0.02 .967
Intervention 9.50 0.51 .330 0.31 0.05 <.001 −0.00 0.02 .948
Difference −0.54 0.71 .449 0.24 0.07 .001 −0.00 0.03 .940
Conners 3 Parent–Inattentiond Control 61.77 2.32 <.001 −0.07 0.19 .708 −0.05 0.08 .507
Intervention 63.73 2.42 <.001 −0.73 0.20 <.001 −0.03 0.08 .687
Difference 1.96 3.35 .560 −0.65 0.28 .019 0.02 0.11 .851
Conners 3 Parent–Exec Functiond Control 59.33 2.26 <.001 0.04 0.19 .830 −0.06 0.08 .412
Intervention 62.47 2.36 <.001 −0.67 0.20 <.001 −0.01 0.08 .905
Difference 3.13 3.27 .340 −0.71 0.27 .010 0.05 0.11 .618
BRIEF–Working Memoryd Control 60.50 2.19 <.001 −0.07 0.15 .637 −0.12 0.06 .057
Intervention 60.63 2.30 <.001 −0.34 0.16 .033 −0.01 0.06 .866
Difference 0.13 3.17 .967 −0.27 0.22 .223 0.11 0.09 .214
BRIEF–Metacognition Indexd Control 58.04 1.95 <.001 −0.11 0.13 .387 −0.07 0.05 .183
Intervention 59.53 2.05 <.001 −0.40 0.13 .003 −0.04 0.05 .474
Difference 1.49 2.83 .599 −0.29 0.18 .111 0.03 0.07 .654
CPT-II–Omissionsd Control 50.93 2.00 .644 0.57 0.18 .002 −0.18 0.07 .015
Intervention 51.24 2.08 .553 −0.07 0.19 .713 0.02 0.07 .793
Difference 0.32 2.89 .912 −0.64 0.26 .015 0.19 0.10 .055
CPT-II–Hit RTd Control 49.61 1.75 .824 0.25 0.13 .058 −0.06 0.05 .231
Intervention 50.26 1.83 .886 −0.22 0.14 .116 0.01 0.05 .803
Difference 0.65 2.53 .797 −0.47 0.19 .015 0.08 0.08 .306
WJ-III–Reading Fluencyb Control 90.04 3.10 .002 0.40 0.12 .001 0.00 0.05 .985
Intervention 97.57 3.24 .456 0.18 0.12 .155 0.04 0.05 .346
Difference 7.52 4.49 .097 −0.23 0.17 .193 0.04 0.07 .521
WJ-III–Math Fluencyb Control 87.95 2.53 <.001 0.17 0.14 .243 −0.05 0.06 .396
Intervention 89.53 2.67 <.001 0.09 0.15 .538 −0.12 0.06 .040
Difference 1.59 3.68 .667 −0.08 0.20 .710 −0.07 0.08 .395

Note. WISC-IV = Wechsler Intelligence Scale for Children–Fourth Edition; BRIEF = Behavior Rating Inventory of Executive Function; CPT-II = Conners’ Continuous Performance Test–Second Edition; Hit RT = Hit Reaction Time; WJ-III = Woodcock Johnson Tests of Achievement–Third Edition.

*p-values are from piecewise linear mixed-effect models. p-values for intercepts are for baseline estimates relative to published normative mean scores. p-values for Slope 1 are for slope estimates in comparison to zero indicating whether there was a significant change from baseline to immediate postassessment for the control group, intervention group, or a comparison between the control group and intervention group slopes (difference), respectively. p-values for Slope 2 are for slope estimates in comparison to zero indicating whether there was a significant change from immediate postassessment to 6-month postassessment for the control group, intervention group, or a comparison between the control group and intervention group slopes (difference), respectively.

aScaled Score: mean = 10, standard deviation = 3; higher score is better.

bStandard Score: mean = 100, standard deviation = 15; higher score is better.

cPrimary intervention outcome.

dT Score: mean = 50, standard deviation = 10; higher score is worse.