EQAS Program User Guide - QCNet

Chapter 5: EQAS Reports2Mean Z-score (summary of all analytes reported by instrument)This section shows your registered analytes in alphabetical order by instrument with the followinginformation:• Analyte name• Your Mean |Z-score|The mean of your reported individual sample absolute Z-score values (no negative values aredisplayed).• Your PercentileThe overall distribution for your peer mean |Z-score| values is displayed. Your mean |Z-score| isexpressed as the percentile of this distribution. A 50% percentile indicates your result is in the centerof the distribution. In this case, there would be as many laboratories with a lower |Z-score| and asmany laboratories with a higher |Z-score| than your laboratory. If you are the only lab in the peergroup, no comparison will be possible and a dash (-) will be displayed.• Mean |Z-score| DistributionThis is a visual representation of the mean |Z-score| distribution. The 10%, 50%, and 90% |Z-score|is shown for your reference and your result is shown as a diamond () on the distribution line. Thelowest percentiles represent the lowest mean |Z-score|. Therefore, a laboratory located at the leftside of the distribution has a lower then average mean |Z-score|. If you are located at the right sideof the distribution, your laboratory’s mean |Z-score| is higher than the average mean |Z-score|(shown as the 50% percentile). A lower percentile represents better performance and less bias. Ifyou are the only lab in the peer group, no distribution values will be displayed.66 EQAS Program User Guide