Table 5.

Correlation between the percentage of safe instruments used and the number of injuries based on linear regression beginning from the start of the implementation of use of safe instruments in 2008

	Assessment considering the study bias	Correlation coefficient (r)	r2	P value	F value
Percentage of used unsafe venipuncture cannulae and injuries due to venipuncture cannulae at selected surgical and internal medicine departments	2008–2012	–0.9808	0.9619	0.0032	75.23
	without 2009	–0.9803	0.9609	0.0197	49.21
	without 2008	–0.9088	0.8259	0.0912	9.49
Percentage of used unsafe venipuncture cannula, injection needles, portacath needles, and lancets and injuries due to these instruments at selected internal medicine departments	2008–2012	–0.6489	0.4211	0.2361	2.18
	without 2009	–0.7473	0.5584	0.2527	2.53
	without 2008	–0.9126	0.8329	0.0874	9.97