Data quality
Over the years the data quality of the Victorian Birth Defects Register (VBDR) has been assessed by validation studies. The first, conducted in 1986, found that the proportion of birth defects notified to the VBDR improved from 35% to 48% during the period 1982-1985. The second study, conducted in 1993, also reported a marked improvement in notification rates from 50% to 86% during the period 1989-1992. The most recent study done in 2001 noted again further improvement in notification to 88%. However, there is always room for improvement, and ascertainment of all terminations remains difficult.
Since 1992 the VBDR has been updated from hospital inpatient listings from the Royal Children's Hospital (RCH) detailing all children born since 1982 who have subsequently been admitted to the RCH with a birth defect. We have also obtained listings of all children born since 1982 who have visited the RCH Cardiology Unit and Genetic Health Services Victoria Metabolic Clinic, either as an inpatient or outpatient. This procedure has also been adopted for Monash Medical Centre where the inpatient listings date back to 1992.