Table 1.
Predictive validity: Comparison of children with and without a CD diagnosis at 5 years of age on outcome measures at age 10
| Child functioning at age 10 | Age 5 diagnostic grouping
|
Group difference | Effect size | |
|---|---|---|---|---|
| Children with CD (N = 184) | Children without CD (N = 1954)a | |||
| Behavioural outcomes | ||||
| Mother’s report | M (SD) | M (SD) | t (df)b | d c |
| Attention deficit hyperactivity (ADHD) symptom scale | 14.8 (8.2) | 8.0 (6.9) | 9.55 (1068)*** | 0.89 |
| Aggression scale | 15.4 (8.7) | 7.2 (6.0) | 11.23 (1068)*** | 1.10 |
| Delinquency scale | 4.0 (3.3) | 1.5 (1.9) | 9.50 (1068)*** | 0.93 |
| Emotional problem scale | 9.7 (7.6) | 6.2 (5.2) | 5.43 (1068)*** | 0.54 |
| Prosocial behaviour scale | 15.0 (3.6) | 17.2 (2.7) | 7.55 (1068)*** | 0.70 |
| Teacher’s report | ||||
| ADHD symptom scale | 6.9 (8.1) | 3.3 (5.5) | 4.98 (990)*** | 0.52 |
| Aggression scale | 9.3 (10.2) | 3.6 (6.6) | 6.70 (991)*** | 0.67 |
| Delinquency scale | 1.8 (2.5) | 0.6 (1.4) | 5.86 (989)*** | 0.62 |
| Emotional problem scale | 5.5 (6.2) | 4.8 (5.7) | 1.36 (991) | 0.13 |
| Prosocial behaviour scale | 11.9 (4.9) | 14.1 (4.6) | 4.77 (982)*** | 0.47 |
| N (%) | N (%) | Odds ratio (95% CI) | ||
| Received treatment for behavioural/emotional problems | 65 (36.2) | 286 (14.3) | 3.4 (2.3, 5.1)*** | 0.68 |
| Educational outcomes | ||||
| Special education service use | 53 (27.3) | 244 (11.6) | 2.9 (1.9, 4.4)*** | 0.59 |
| Standard reading score below average or poor | 62 (30.1) | 335 (15.0) | 2.4 (1.6, 3.7)*** | 0.48 |
| English school performance below average | 83 (47.3) | 512 (25.8) | 2.6 (1.7, 3.8)*** | 0.53 |
| Math school performance below average | 73 (43.3) | 465 (23.9) | 2.4 (1.7, 3.5)*** | 0.48 |
| M (SD) | M (SD) | t (df) | ||
| Teacher’s effort scale | 16.4 (9.1) | 11.3 (7.8) | 6.30 (989)*** | 0.60 |
Five CD children and 89 comparison children were missing parent data at age 10; an additional 21 CD and 191 comparison children were missing teacher data at age 10. Ns are unweighted; proportions are weighted to represent the population of British families
Continuous variables were analysed with t-tests and their degrees-of-freedom (df) and categorical variables with odds ratios (OR) and their 95% confidence intervals (CI). Standard errors, 95% CIs, and test statistics include adjustments for the dependence in the data due to analyzing two children in the same family [39]. Thus, degrees-of-freedom are based on number of families rather than number of children
Differences between groups can be interpreted in terms of standard deviation units (d), where d = 0.2 is considered a small effect size, d = 0.5 is a medium effect size, and d = 0.8 is a large effect size [8]
P ≤ 0.001