Bioequivalence and Bioavailability Forum

Dear NewInPK!

❝ I've used RE(%) = Accuracy for a long time. However lately I am debating

❝ if I should join the ranks of those who use RE(%) = Inaccuracy.

❝

❝ RE(%) = 100*(measured - theoretical)/theoretical

Welcome to the club!

❝ In many math books Accuracy is described as RE, which means that the lower

❝ the RE, the better the accuracy. However in day to day language, I'd rather

❝ be 100% accurate, then 1% accurate.

Yes!

❝ In one place I noticed the term "Relative Accuracy Error", which

❝ mitigates my dilemma a little better.

Hhm, I'm not a native English speaker - sounds a little bit weird to me. I must confess that I used both Accuracy and Inaccuracy in conversation - it was always clear from the context, which term I actually meant. In my reports I try to use Inaccuracy.

❝ Should we use Inaccuracy, Accuracy, or Relative Accuracy Error?

I would say:

• Accuracy = 100*measured/theoretical, whereas
  
• Inaccuracy = 100*(measured - theoretical)/theoretical

The Arlington III Whitepaper states for LBAs:

For a method to be considered acceptable, it is recommended that both the interbatch imprecision (%CV) and the accuracy, expressed as absolute mean bias (%RE) be ±20% (25% at LLOQ and ULOQ). As an additional constraint to control method error, it is recommended that the target total error (sum of the absolute value of the %RE [accuracy] and precision [%CV] be less than ±30% [±40% at the LLOQ and ULOQ]).

❝ Also, is %Bias = %RE?

IMHO, yes.

❝ Same goes for precision.

That's nasty. Arlington III again:

[...] the major sources of variability [are] imprecision and inaccuracy.

To quote William S. Burroughs:

Language is a virus from outer space!