Measurement Precision
Quality assurance programs in material testing laboratories calculate the variance between two identical test runs to verify the consistency of their methods. The relative percent difference measures the difference between duplicate test results divided by their average value, expressed as a percentage. This metric shows the precision of the testing process, with a lower percentage indicating higher reliability and consistency.
Lab Replication
To calculate this metric, a lab analyst tests two separate specimens from the same fabric roll under identical conditions. The relative percent difference is used to monitor the variation in results for properties like yarn count, bursting strength, or fabric weight. If the two tests yield different results, it suggests that the testing equipment is not calibrated or that the fabric is highly irregular.
Margin Tolerance
Testing standards define acceptable limits for the difference between duplicate runs to ensure results are reliable. A typical target is a relative percent difference of less than ten percent for physical fabric tests, and less than fifteen percent for complex chemical analysis. If the calculated difference exceeds these limits, the lab must reject the test run and start again.
Process Improvement
Tracking the consistency of test results helps laboratories identify areas where their staff or equipment need improvement. By analyzing trends in the relative percent difference over time, lab managers can spot issues like operator bias, worn testing parts, or poor sample preparation. This continuous monitoring ensures that the lab’s reports remain highly accurate, giving apparel brands confidence in the quality of their certified fabrics.
