An empirical test of the evidential reasoning approach’s synthesis axioms

This paper reports results from two empirical tests of the descriptive validity of synthesis axioms used by the evidential reasoning (ER) approach to aggregate performance over multiple criteria. These show that evaluations which invoke the axioms frequently violate them. The two most systematic aspects of the violations are that aggregate evaluations tend to be more favourable than basic evaluations, and that small amounts of ignorance on one attribute may be compensated for by complete assessments on other attributes. The implications for prescriptive use of the ER approach are discussed and some practical assessment procedures suggested.