<p>A new method is presented for assessing the degree of accuracy in the etymologies of ethnonyms (tribal names) based on the number of expert rules executed within the rule-based expert system. Since expert rules predominantly reflect sporadic rather than regular linguistic changes in etymological chains, it is impossible to distinguish between rules using the certainty factor technique. Additionally, it is wellknown that a multidisciplinary approach is crucial for verifying ethnonyms’ etymologies. However, nonlinguistic multidisciplinary information supporting particular etymologies is exceedingly rare. Therefore, this work introduces a novel method that complements the multidisciplinary approach and addresses the sporadic nature of rules. This method evaluates the possibility of N linguistic changes occurring within the etymological chain of predominantly sporadic rules based on the correlation between the number of linguistic changes from the initial hypothetical etymon (source) to the final ethnonym (target) and the length of the etymon in the characters. The study presents the JAVA code of the algorithm for the proposed method. The application of this method was demonstrated through the evaluation of the etymology of two sample ethnonyms from the list of 22 Oghuz ethnonyms, which originate from a medieval confederation of 24 Oghuz Turkic tribes. The results of these assessments highlight the effectiveness of the new method as a reliable tool for evaluating the accuracy of ethnonyms’ etymologies to a certain extent, especially in situations where multidisciplinary confirmation is absent.</p>