The proportion of children referred for specialist assessment in the prospective and retrospective cohorts at ages 9, 18 and 30 months
| Age (months) | Retrospective cohort (January–December 2018) | Prospective cohort (July–December 2019) | % difference (95% CI) | P value | ||||
| N | N Ref | % (95% CI) | N | N Ref | % (95% CI) | |||
| 9 | 3085 | 53 | 1.7% (1.3% to 2.3%) | 972 | 4 | 0.4% (0.01% to 0.8%) | −1.31% (−2.16% to −0.46%) | 0.003 |
| 18 | 2074 | 73 | 3.5% (2.7% to 4.3%) | 687 | 49 | 7.1% (5.2% to 1.9%) | 3.61% (1.84% to 5.38%) | <0.001 |
| 30 | NA | 51 | – | 41 | 4 | 9.76 | – | – |
95% CI, calculated using normal approximation (z-statistic); N, Total number of children who were screened for developmental concerns at the primary care center; NA, not available; NRef, Number of children referred for specialist assessment.