Quality
Why one analytical method is not the whole picture
The logic of orthogonal techniques and measuring different critical attributes.
A method is designed for a particular analytical attribute and reportable range. Selectivity adequate for one question may not be adequate…
02Orthogonal evidenceTwo techniques are usefully orthogonal when they rely on different physicochemical principles. Agreement can increase confidence, while disagreement can reveal interference…
03A risk-based strategyTest selection should connect to attributes critical for the research purpose and to the risk of a wrong conclusion. Documentation explains…
Every method has a scope
A method is designed for a particular analytical attribute and reportable range. Selectivity adequate for one question may not be adequate for another. Sound evaluation starts with purpose, not with how advanced the instrument sounds.
Orthogonal evidence
Two techniques are usefully orthogonal when they rely on different physicochemical principles. Agreement can increase confidence, while disagreement can reveal interference or a faulty assumption. The second method should add information, not merely another graph.
A risk-based strategy
Test selection should connect to attributes critical for the research purpose and to the risk of a wrong conclusion. Documentation explains why each method was selected and what uncertainty remains after measurement.
LABORATORY APPLICATION
Turning the principle into an auditable record
Create an attribute–method–risk matrix. For each attribute record what the primary method measures, which orthogonal confirmation exists and what interference remains plausible. The matrix helps avoid both unnecessary testing and unrecognised gaps.
PRIMARY & OFFICIAL SOURCES
Sources and further reading
COMMON QUESTIONS
Questions specific to this topic
What is an orthogonal method?
A method using a different measurement principle that adds independent information about the same attribute.
Are multiple methods always needed?
No. Number and type depend on purpose, risk of error and performance of the primary method.
What if methods disagree?
Preparation, standards, interference and suitability are reviewed before a conclusion is made.