TABLE 5.

Crude and adjusted associations between the testing method, accreditation status and satisfactory/unsatisfactory (reference category) proficiency testing scores among Canadian environment testing laboratories who were enrolled in external quality assessment (EQA) which includes proficiency testing (PT) program from 2016–2022.

	Unadjusted odds ratio (95% CI)	Adjusted odds ratio (95% CI)
Testing Method
EST	1.0 (Ref)	1.0 (Ref)
MF	1.84 (1.49, 2.28)***	1.75 (1.37, 2.24)***
MPN	0.97 (0.70, 1.33)	0.85 (0.58, 1.23)
Accreditation status to ISO/IEC 17025
No	1.0 (Ref)	1.0 (Ref)
Yes	1.60 (1.31, 1.95)***	1.47 (1.16, 1.85)***
Rural location status
No	1.0 (Ref)	1.0 (Ref)
Yes	1.54 (0.76, 3.14)	1.85 (0.89, 3.82)
Testing time post shipment
<96 h	1.0 (Ref)	1.0 (Ref)
≥96 h	0.22 (0.18, 0.26)***	0.76 (0.59, 0.98)*
Year of program participation
2016	1.0 (Ref)	1.0 (Ref)
2017	1.48 (1.04, 2.11)*	1.78 (1.13, 2.80)*
2018	1.33 (0.93, 1.90)	1.62 (1.03, 2.56)*
2019	1.22 (0.88, 1.71)	1.17 (0.78, 1.74)
2020	1.43 (1.01, 2.02)*	1.46 (0.96, 2.22)
2021	1.87 (1.28, 2.72)**	1.53 (1.01, 2.32)*
2022	1.28 (0.91, 1.81)	1.05 (0.71, 1.54)

*p < 0.05, **p < 0.01, ***p < 0.001. CI, confidence interval.