# Testing bias against allowable bias

Test if the bias meets performance requirements; that is the bias is less than allowable bias.

If the bias from a study is less than the allowable bias, it meets the performance requirements, but you cannot make any statements relating to probability. An equivalence test allows you to make statements with a given level of confidence about what you observed.

1. Activate the analysis report worksheet.
2. On the Analyse-it ribbon tab, in the Bias group, click Test Equivalence.
The analysis task pane Trueness panel opens.
3. Optional: In the Significance level edit box, type the maximum probability of rejecting the null hypothesis when in fact it is true (typically 5% or 1%) and if required select the Familywise error rate check box.
Note: CLSI EP15 uses a 5% familywise significance level so the overall significance level is a maximum of 5% regardless of the number of comparisons (for example, for 1 level the significance level is 5%, for 2 levels the significance level is 5%/2 = 2.5% for each level, for 3 levels the significance level is 5%/3 = 1.6% for each level).
4. Enter the performance requirements:
• If the allowable bias is a constant or proportional value across the measuring interval, select Across measuring interval, and then in the Absolute edit box, type the bias in measurement units, and/or in the Relative edit box, type the bias as a percentage (suffix with % symbol).
Note: The allowable bias is the greater of the absolute bias and the relative bias for each level. Therefore, with a absolute bias of 5mg/dL and a relative bias of 10%, the allowable bias will be set at 5mg/dL for all values 0 mg/dL up to 50mg/dL and then at 10% of assigned value for values above 50mg/dL.
• If the allowable bias varies for each level, select Each level and then in the Allowable bias grid, under the Absolute / Relative column, alongside each level, type the absolute bias in measurement units, or the relative bias as a percentage (suffix with % symbol).
5. Click Recalculate.

Published 8-Jan-2017
Version 4.90