Figure 1.

Proportion of medication errors before and after implementation of computerised physician order entry (CPOE) using the Clinical Information System with 95% confidence intervals. Hand-written prescribing (HWP) data collection began on the following dates: 17 September 2001 for 5 days; 24 September 2001 for 4 days (merged with the previous period). CPOE data collection began on the following dates: 15 April 2002 for 5 days; 10 June 2002 for 2 days; 27 September 2002 for 5 days; and 18 December 2002 for 5 days.