Table 4.

Types of prescribing errors and near misses

	Number (%)	Rate per 100 prescriptions (95% CI)*
	Overall	Rate	95% CI
No of prescriptions	9385
Prescribing errors† (N)	19 956	212.6	(186.2 to 243.0)
Type of error
Illegibility errors	16 513 (82.8)	175.1	(148.6 to 206.3)
Inappropriate abbreviation	1230 (6.2)	13.1	(8.2 to 20.9)
Directions error	394 (2.0)	4.2	(3.4 to 5.1)
Strength error	392 (2.0)	4.2	(3.4 to 5.2)
Dose error	344 (1.7)	3.7	(2.5 to 5.3)
Length of treatment error	333 (1.7)	3.5	(2.4 to 5.2)
Frequency error	192 (1.0)	2.0	(1.6 to 2.7)
Amount error	172 (0.9)	1.8	(1.3 to 2.7)
Other errors‡	386 (1.7)	4.1	(3.2 to 5.4)
Near misses (N)	142	1.5	(1.2 to 1.9)
Type of error
Illegibility errors	38 (26.8)	0.40	(0.31 to 0.63)
Frequency error	27 (19.0)	0.29	(0.18 to 0.42)
Directions error	22 (15.5)	0.23	(0.15 to 0.35)
Dose error	14 (9.0)	0.14	(0.08 to 0.25)
Strength error	11 (7.7)	0.12	(0.06 to 0.21)
Route error	3 (2.1)	0.03	(0.007 to 0.09)
Inappropriate abbreviation	2 (1.4)	0.02	(0.003 to 0.08)
Other errors§	25 (17.6)	0.26	(0.17 to 0.39)

^*Cluster-adjusted Poisson CI.

^†Excluding rule violations.

^‡For example, refill errors.

^§For example, drug–drug interaction errors.