Bayesian treatment of results from radioanalytical measurements. Effect of prior information modification in the final value of the activity

Abstract

We address the problem of evaluating measurements of radionuclide activity concentration from a robust Bayesian perspective. As shown in previous studies, Bayesian incorporation of available prior information on the activity levels, together with the measured values, leads in general to an improvement in the quality of radioanalytical results. Since the specific form of the employed prior is a critical aspect of the Bayesian framework, in the present paper we distort the prior distribution in order to evaluate how it influences the final activity estimate. We applied this procedure to inter-laboratory proficiency test data obtained by the laboratories that perform radiochemical analysis for the Spanish radioactive monitoring network. We found that in the present application the Bayesian methodology is indeed robust, as modifying the specific form of the prior has little effect on the activity estimate. Similar sensitivity analysis could be applied to the Bayesian evaluation of measurements of other quantities for which prior knowledge is available.