Characteristics of those who participated in either a WALNA or NAPLAN test between 1989 and 2007 (n=45 697 children) for exposed and comparison cohorts by Indigenous status
| Variable | Non-Indigenous | Indigenous | ||
| Exposed (n=7804) | Comparison (n=22 107) | Exposed (n=4887) | Comparison (n=10 899) | |
|---|---|---|---|---|
| Frequency matching variables | % | % | % | % |
| Maternal age | ||||
| <20 years | 12.4 | 12.6 | 25.2 | 24.4 |
| 20–24 years | 29.5 | 29.3 | 34.3 | 34.2 |
| 25–29 years | 29.2 | 28.8 | 23.6 | 24.2 |
| 30+ years | 28.9 | 29.2 | 16.9 | 17.2 |
| Child’s year of birth | ||||
| 1989–1993 | 34.6 | 34.3 | 36.4 | 34.6 |
| 1994–1998 | 36.5 | 35.6 | 36.0 | 35.5 |
| 1999–2003 | 29.0 | 30.0 | 27.6 | 30.0 |
| Maternal characteristics during pregnancy | ||||
| Marital status | ||||
| Married | 73.7 | 85.8 | 60.0 | 66.5 |
| Never married | 22.8 | 13.4 | 37.5 | 31.5 |
| Separated/divorced/widowed | 3.1 | 0.8 | 1.9 | 1.6 |
| Missing* | 0.3 | 0.1 | 0.6 | 0.4 |
| SEIFA – area of residence | ||||
| Most disadvantaged >10% | 3.7 | 6.5 | 0.2 | 0.5 |
| 10 to <25% | 8.9 | 12.0 | 1.0 | 1.8 |
| 25 to <50% | 18.6 | 22.4 | 5.0 | 7.4 |
| 50 to <75% | 25.3 | 24.7 | 13.5 | 17.3 |
| 75 to <90% | 19.6 | 15.8 | 19.0 | 21.6 |
| Most disadvantaged 10% | 15.8 | 9.9 | 29.6 | 30.3 |
| Missing* | 8.2 | 8.6 | 31.7 | 21.0 |
| Health service region | ||||
| Perth metro | 71.7 | 72.3 | 32.2 | 34.0 |
| Rural/remote | 28.3 | 27.7 | 67.8 | 66.0 |
| Illicit drug use record | 39.4 | 1.7 | 25.3 | 5.4 |
| Mental disorder (other than substance use) | 53.3 | 9.1 | 32.9 | 12.6 |
| Maternal smoking | 51.8 | 22.2 | 66.6 | 44.3 |
| Parity | ||||
| 0 | 38.8 | 49.2 | 23.7 | 28.9 |
| 1 | 30.3 | 31.4 | 21.8 | 24.0 |
| 2 | 17.6 | 13.1 | 19.6 | 18.5 |
| 3+ | 13.3 | 6.2 | 34.8 | 28.5 |
| Child characteristics | ||||
| Male | 49.1 | 49.1 | 49.9 | 48.7 |
| Low birth weight (<2500 g)* | 9.8 | 5.4 | 17.7 | 9.5 |
| Preterm (gestational age <37 weeks) | 9.7 | 6.0 | 16.3 | 10.2 |
| School achievement | ||||
| Number of tests (observations) | 21 385 | 60 716 | 11 061 | 27 002 |
| Mean number of tests | 2.74 | 2.75 | 2.26 | 2.48 |
Note: Maternal smoking is restricted to birth years from 1998 onwards (n=17 631).
*117 missing cases for marital groups; 3 missing cases for birth weight; 6379 missing cases for SEIFA.
NAPLAN, National Assessment Program – Literacy and Numeracy; SEIFA, Socio-Economic Index for Areas; WALNA, Western Australian Literacy and Numeracy Assessment.