What are the basic comparison statistics in the Unity Interlaboratory Program and what do they indicate about Lab Performance?
The CVR evaluates your imprecision compared to the consensus group. CVR is calculated as follows.
CVR = Your CV/Consensus Group CV
If your test imprecision is equal to that of the consensus group the CVR will be 1.0.
CVR<1 indicates acceptable performance.
1<CR<1.5 indicates acceptable to marginal performance, may need to investigate test system imprecision.4
CVR>1.5 indicates marginal performance, may need to perform corrective action.
The SDI evaluates your bias compared to the consensus group. SDI is calculated as follows.
SDI = Your Mean - Consensus Group Mean/Consensus Group SD
The target SDI is 0.0 which indicates your mean is identical to the consensus group mean.
-1<SDI<1 indicates acceptable performance.
1<SDI<1.5 or -1<SDI<-1.5 indicates acceptable or marginal performance, may need to investigate test system bias.
SDI>1.5 or SDI<-1.5 indicates marginal performance, may need to perform corrective action.