Supplementary Information for “Validity of the ADHD-IV rating scale in youth with autism”
Table S1. Comparison of sample with and without Teacher report
Caregiver Report / Caregiver & Teacher Report / p-value / Cohen’s dSample Size / 183 / 203
Chronological Age (Years)
M (SD) / 10.70 (2.92) / 10.40 (3.11) / 0.337 / 0.10
Min - Max / 6.00 – 18.58 / 6.08 – 18.83
GCA
M (SD) / 101.01 (18.72) / 99.81 (17.55) / 0. 519 / 0.07
Min - Max / 61 – 162 / 67 – 158
Verbal Reasoning
M (SD) / 101.37 (19.88) / 100.29 (18.03) / 0.578 / 0.06
Min – Max / 60 – 153 / 62 – 161
Nonverbal Reasoning
M (SD) / 101.46 (18.56) / 100.26 (16.84) / 0.504 / 0.07
Min - Max / 61 – 152 / 64 – 166
Spatial Reasoning
M (SD) / 99.43 (15.95) / 99.06 (16.18) / 0.824 / 0.02
Min - Max / 62 – 150 / 63 – 141
Sex-Ratio (M:F) / 156:27 / 186:17 / 0.070 / 0.18
ADI-R
Social Interaction / 18.54 (5.71) / 18.73 (6.52) / 0.836 / 0.03
Communication / 14.87 (4.53) / 15.00 (4.85) / 0.842 / 0.03
Repetitive Behaviors / 5.64 (2.42) / 5.93 (2.49) / 0.253 / 0.12
ADOS-2
Total M (SD) / 11.61 (4.93) / 12.85 (4.89) / 0.019 / 0.25
Social Affect M (SD) / 8.67 (4.02) / 9.47 (4.14) / 0.071 / 0.20
Repetitive Behavior M (SD) / 2.94 (1.88) / 3.39 (1.94) / 0.026 / 0.24
CSS M (SD) / 6.60 (2.43) / 7.07 (2.19) / 0.050 / 0.20
CSS=Calibrated Severity Score
Table S2. ADHD Rating Scale – Caregiver Report Item Characteristics
Item Number and abbreviated Content / Mean / SD / N(%) above cut-off / Item-total correlation1. Fails to give close attention/careless mistakes / 1.62 / 0.97 / 200 (52%) / 0.70
2. Fidgets or squirms in seat / 1.75 / 1.01 / 235 (61%) / 0.65
3. Difficulty sustaining attention in tasks or play / 1.56 / 0.95 / 186 (48%) / 0.68
4. Leaves seat when expected to sit / 1.12 / 1.04 / 125 (32%) / 0.68
5. Doesn’t listen when spoken to directly / 1.46 / 0.86 / 175 (45%) / 0.63
6. Runs or climbs excessively inappropriately / 0.78 / 0.94 / 86 (22%) / 0.67
7. Doesn’t follow instructions and finish work / 1.37 / 0.95 / 159 (41%) / 0.70
8. Difficulty playing quietly / 0.94 / 0.91 / 102 (26%) / 0.64
9. Difficulty organizing tasks and activities / 1.85 / 0.92 / 248 (64%) / 0.63
10. “On the go” or “driven by a motor” / 1.10 / 1.08 / 127 (33%) / 0.65
11. Avoids tasks that require sustained effort / 1.59 / 1.04 / 197 (51%) / 0.68
12. Talks excessively / 1.39 / 1.08 / 164 (42%) / 0.63
13. Loses necessary items for tasks / 1.34 / 0.98 / 155 (40%) / 0.66
14. Blurts out answers / 1.25 / 1.05 / 139 (36%) / 0.65
15. Is easily distracted / 1.91 / 0.95 / 252 (65%) / 0.73
16. Difficulty waiting their turn / 1.50 / 1.01 / 173 (45%) / 0.66
17. Forgetful in daily activities / 1.44 / 1.00 / 169 (44%) / 0.66
18. Interrupts or intrudes on others / 1.82 / 0.93 / 245 (63%) / 0.71
Table S3. ADHD Rating Scale – Teacher Report Item Characteristics
Item Number and abbreviated Content / Mean / SD / N(%) above cut-off / Item-total correlation1. Fails to give close attention/careless mistakes / 1.36 / 0.96 / 80 (39%) / 0.64
2. Fidgets or squirms in seat / 1.56 / 1.11 / 98 (48%) / 0.64
3. Difficulty sustaining attention in tasks or play / 1.56 / 1.00 / 94 (46%) / 0.73
4. Leaves seat when expected to sit / 0.79 / 0.96 / 43 (21%) / 0.67
5. Doesn’t listen when spoken to directly / 1.00 / 0.91 / 54 (27%) / 0.60
6. Runs or climbs excessively inappropriately / 0.28 / 0.64 / 13 (6%) / 0.58
7. Doesn’t follow instructions and finish work / 1.17 / 0.97 / 67 (33%) / 0.64
8. Difficulty playing quietly / 0.63 / 0.85 / 31 (15%) / 0.64
9. Difficulty organizing tasks and activities / 1.43 / 0.95 / 94 (46%) / 0.69
10. “On the go” or “driven by a motor” / 0.61 / 0.85 / 28 (14%) / 0.65
11. Avoids tasks that take sustained effort / 1.01 / 0.97 / 57 (28%) / 0.66
12. Talks excessively / 0.86 / 0.94 / 46 (23%) / 0.66
13. Loses necessary items for tasks / 0.83 / 0.94 / 40 (20%) / 0.64
14. Blurts out answers / 1.00 / 1.00 / 58 (29%) / 0.67
15. Is easily distracted / 1.70 / 0.98 / 108 (53%) / 0.74
16. Difficulty waiting their turn / 1.04 / 0.98 / 58 (29%) / 0.66
17. Forgetful in daily activities / 0.91 / 0.89 / 45 (22%) / 0.61
18. Interrupts or intrudes on others / 1.17 / 0.98 / 67 (33%) / 0.72
Table S4. Three-factor Exploratory Factor Analytic Solution for the Caregiver Ratings
Pattern CoefficientsItems by Proposed Factors / Factor I / Factor II / Factor III / Communality
Inattentive factor
1 / .716 / .241 / -.102 / .652
3 / .456 / .545 / -.158 / .614
5 / .381 / .328 / .082 / .438
7 / .778 / .166 / -.082 / .690
9 / .743 / -.040 / .077 / .582
11 / .611 / .154 / .066 / .542
13 / .800 / -.185 / .210 / .695
15 / .417 / .388 / .140 / .613
17 / .814 / -.106 / .121 / .686
Hyperactivity factor
2 / .157 / .591 / .063 / .515
4 / .083 / .677 / .122 / .629
6 / .040 / .690 / .172 / .663
8 / .105 / .421 / .308 / .489
10 / -.113 / .696 / .281 / .671
12 / .033 / .224 / .567 / .528
Impulsiveness factor
14 / .174 / .010 / .688 / .626
16 / -.035 / .312 / .585 / .600
18 / .086 / .053 / .835 / .826
Factor correlations
I / – / .483 / .514
II / – / – / .477
Note. Salient loadings (≥ .30) in bold.
Table S5. Two-factor Exploratory Factor Analytic Solution for the Home Scale
Pattern CoefficientsItems by Proposed Factors / Factor I / Factor II / Communality
Inattentive factor
1 / .776 / .024 / .628
3 / .450 / .316 / .503
5 / .381 / .330 / .431
7 / .855 / -.043 / .681
9 / .824 / -.095 / .577
11 / .660 / .105 / .545
13 / .871 / -.112 / .634
15 / .408 / .437 / .608
17 / .902 / -.129 / .667
Hyperactivity/Impulsivity factor
2 / .109 / .600 / .463
4 / .018 / .743 / .571
6 / -.039 / .812 / .617
8 / .039 / .676 / .496
10 / -.225 / .951 / .653
12 / -.031 / .714 / .480
14 / .146 / .574 / .468
16 / -.114 / .826 / .563
18 / .055 / .732 / .596
Factor correlations
I / – / .704
Fit Indices
BIC / 308.9
RMSEA / .142
RMSR / .059
Note. Salient loadings (≥ .30) in bold. BIC is the Bayes Information Criterion, RMSEA is the Root Mean Square Error of Approximation, and RMSR is the Root Mean Square of the Residuals.
Table S6 Three-factor Exploratory Factor Analytic Solution for the Teacher Ratings
Pattern CoefficientsItems by Proposed Factors / Factor I / Factor II / Factor III / Communality
Inattentive factor
1 / .618 / .090 / .065 / .499
3 / .219 / -.046 / .810 / .883
5 / .327 / .179 / .250 / .398
7 / .771 / -.071 / .093 / .642
9 / .814 / .033 / .008 / .695
11 / .553 / .102 / .169 / .529
13 / .809 / .067 / -.062 / .645
15 / .266 / .188 / .518 / .683
17 / .770 / -.050 / .042 / .601
Hyperactivity factor
2 / .039 / .195 / .605 / .554
4 / -.091 / .608 / .368 / .634
6 / .064 / .591 / .255 / .617
8 / .123 / .588 / .116 / .521
10 / .003 / .561 / .324 / .596
12 / -.016 / .800 / .070 / .685
Impulsiveness factor
14 / .140 / .838 / -.132 / .715
16 / -.107 / .934 / .000 / .794
18 / .104 / .904 / -.117 / .809
Factor correlations
I / _ / .445 / .625
II / _ / – / .475
Note. Salient loadings (≥ .30) in bold.
Table S7. Two-factor Exploratory Factor Analytic Solution for the School Scale
Pattern CoefficientsItems by Proposed Factors / Factor I / Factor II / Communality
Inattentive factor
1 / .667 / .056 / .487
3 / .745 / .121 / .666
5 / .497 / .207 / .398
7 / .851 / -.116 / .634
9 / .820 / -.024 / .653
11 / .677 / .092 / .533
13 / .760 / .001 / .578
15 / .613 / .278 / .633
17 / .806 / -.100 / .574
Hyperactivity factor
2 / .442 / .317 / .444
4 / .136 / .696 / .604
6 / .214 / .650 / .615
8 / .175 / .615 / .522
10 / .201 / .637 / .581
12 / -.007 / .832 / .686
14 / .017 / .804 / .661
16 / -.155 / .961 / .791
18 / -.012 / .877 / .758
Factor correlations
I / – / .528
Fit Indices
BIC / 38.9
RMSEA / .155
RMSR / .054
Note. Salient loadings (≥ .30) in bold. BIC is the Bayes Information Criterion, RMSEA is the Root Mean Square Error of Approximation, and RMSR is the Root Mean Square of the Residuals.
Table S8. Correlation Matrix of Age with Caregiver and Teacher report of ADHD Symptom Domains
Age / Caregiver Inattn / Caregiver H/I / Caregiver Total / Teacher Inattn / Teacher H/I / Teacher TotalAge / --
Caregiver Inattn. / -.080 / --
Caregiver H/I / -.312*** / .664*** / --
Caregiver Total / -.218*** / .911*** / .914*** / --
Teacher Inattn / -.213** / .380*** / .250*** / .351*** / --
Teacher H/I / -.284*** / .340*** / .426*** / .393*** / .601*** / --
Teacher Total / -.278*** / .418*** / .383*** / .431*** / .897*** / .891*** / --
**p<.005, *** p < .001
Table S9. Correlation Matrix of ADHD Rating Scale Caregiver Version with Parent-Reported BRIEF Indices
Behavioral Regulation IndexMetacognition IndexGlobal Executive Composite
Inattention.441***.748***.709***
Hyperactivity/Impulsivity.649***.460***.609***
Total.595***.662***.721***
*** p < .001; n=365
Note: Chronological age was covaried for all analyses.
Table 10. Correlation Matrix of ADHD Rating Scale Caregiver Report and BASC-2
Internalizing / ExternalizingInattention / .141 / .490***
Hyperactivity/Impulsivity / .171^ / .669***
Total / .170^ / .634***
^p<.05, ***p<.001; n=127
Figure S1. Distribution of ratings for Item 1 for caregivers (top) and teachers (bottom).
Figure S2. Distribution of ratings for Item 2 for caregivers (top) and teachers (bottom).
Figure S3. Distribution of ratings for Item 3 for caregivers (top) and teachers (bottom).
Figure S4. Distribution of ratings for Item 4 for caregivers (top) and teachers (bottom).
Figure S5. Distribution of ratings for Item 5 for caregivers (top) and teachers (bottom).
Figure S6. Distribution of ratings for Item 6 for caregivers (top) and teachers (bottom).
Figure S7. Distribution of ratings for Item 7 for caregivers (top) and teachers (bottom).
Figure S8. Distribution of ratings for Item 8 for caregivers (top) and teachers (bottom).
Figure S9. Distribution of ratings for Item 9 for caregivers (top) and teachers (bottom).
Figure S10. Distribution of ratings for Item 10 for caregivers (top) and teachers (bottom).
Figure S11. Distribution of ratings for Item 11 for caregivers (top) and teachers (bottom).
Figure S12. Distribution of ratings for Item 12 for caregivers (top) and teachers (bottom).
Figure S13. Distribution of ratings for Item 13 for caregivers (top) and teachers (bottom).
Figure S14. Distribution of ratings for Item 14 for caregivers (top) and teachers (bottom).
Figure S15. Distribution of ratings for Item 15 for caregivers (top) and teachers (bottom).
Figure S16. Distribution of ratings for Item 16 for caregivers (top) and teachers (bottom).
Figure S17. Distribution of ratings for Item 17 for caregivers (top) and teachers (bottom).
Figure S18. Distribution of ratings for Item 18 for caregivers (top) and teachers (bottom).