# Normalized OPSpecs Chart N=4 90% AQA

**This is a Normalized OPSpecs chart 90% AQA (analytical quality assurance) and with N=4 (4 control measurements).**

**This is a Normalized OPSpecs chart 90% AQA (analytical quality assurance) and with N=4 (4 control measurements).**

**This is a discussion of part of the QC Selection Grid.**

Plot your critical-error on the x-axis of this power function graph. Draw a vertical line from that point to intersect the power curves. Where the curves and critical-error meet indicates how much error detection each control rule will provide.

You have many problems to detect, but fortunately medically important errors are large in size and may be detectable. It is recommended that you increase the number of rules to four and apply the 41s rule across two runs (R=2) as a rejection rule. The power curves below show the rejection characteristics within one run (R=1) and across two runs (R=2):

Plot your critical-error on the x-axis of this power function graph. Draw a vertical line from that point to intersect the power curves. Where the curves and critical-error meet indicates how much error detection each control rule will provide.

Plot your critical-error on the x-axis of this power function graph. Draw a vertical line from that point to intersect the power curves. Where the curves and critical-error meet indicates how much error detection each control rule will provide.