Round Robin Testing is a specific type of interlaboratory comparison where the same test specimen is circulated sequentially among participating laboratories — each lab performs the same measurement procedure, reports results, and the data is analyzed to evaluate between-lab consistency and identify outliers.

Round Robin Protocol

• Sample: A stable, homogeneous sample is prepared — must not change during circulation.
• Circulation: Sample travels Lab A → Lab B → Lab C → ... → Lab A (return check for sample stability).
• Blind Testing: Labs may not know the reference value or other labs' results — prevents bias.
• Analysis: ANOVA, z-scores, or $E_n$ numbers evaluate each lab's performance relative to the group.

Why It Matters

• Tool Matching: In semiconductor fabs, round robin testing validates CD-SEM, overlay, and defect tool matching across sites.
• Method Validation: New measurement methods are validated by round robin — demonstrate reproducibility across laboratories.
• Standard Development: Round robin data supports the development of measurement standards (SEMI, ISO, ASTM).

Round Robin Testing is the measurement relay race — circulating a sample among labs to verify that everyone gets the same answer.