The performance of the dual reference duo-trio (DRDT) method using a balanced-reference mode

- The dual reference duo-trio (DRDT) using the COPD cognitive strategy was studied.
- A simulation-derived psychometric function was developed for the DRDT.
- The DRDT is more sensitive and reliable than the conventional duo-trio (DT).
- The DRDT is more powerful than the conventional DT and triangle tests.
- Tables and R/S-Plus codes are provided for the psychometric function of the DRDT.

The balanced-reference duo-trio test using the comparison of distances (COD) strategy is a widely used unspecified discrimination method. However, it suffers lower testing power. A dual reference duo-trio (DRDT) method was proposed recently as an improved duo-trio in the sensory literature. This paper proposes a new cognitive decision strategy for the DRDT, involving the comparison of pairs of distances (COPD) and investigates theoretically the performance of the DRDT based on a simulation-derived psychometric function. The DRDT is compared with the conventional balanced-reference duo-trio (DT) and the triangle methods. Comparison results show that the DRDT assuming the COPD is more sensitive than the conventional DT assuming the COD, and is more powerful than the conventional DT and the triangle methods for both difference testing and similarity/equivalence testing. The averaged generalized power efficiency of the DRDT is about 34% over that of the conventional DT, and is about 13% over that of the triangle method.