Bayesian Analysis (2012) 7, Number 3, pp. 541–546 Rejoinder Isabelle Albert ∗ , Sophie Donnet † , Chantal Guihenneuc-Jouyaux ‡ , Samantha Low-Choy § , Kerrie Mengersen ¶ and Judith Rousseau ‖ We very much appreciated the interesting comments of S. French and J.P. Gosling on our paper and we briefly address their key points. In agreement with the two discussants, we found existing methods for mathematically pooling opinions to be limiting, and hence proposed a Bayesian framework. We thank the discussants for providing this opportunity to address the philosophical issues that give meaning and context to the use of information elicited from experts to construct informative priors. Our rejoinder to the issues raised by discussants can be classified as follows: 1. Modelling elicitation error using a pooled prior. This includes: (a) Practical application of this hierarchical model. (b) Confidence: encoding expert confidence or credibility. (c) Model validation. 2. Ownership of the prior: Decision-maker, group or society? (a) Does this hierarchical prior apply more when the prior is ‘owned’ by the decision-maker? (b) How does it apply when ‘owned’ by a group or more broadly by society? (c) What is the role of a pooled prior: as an end in itself or as information to inform the experts, the decision-maker and their interactions? We first discuss the points raised by S. French. 1 Rejoinder on S. French’s comments First we thank Simon French for considering our approach as useful. The main concern as far as we understand is on when and how should such an approach be considered. ∗ INRA, UR1204, M´ et@risk, AgroParisTech, Paris, France, isabelle.albert@paris.inra.fr † Universit´ e Paris Dauphine, Paris, France, donnet@ceremade.dauphine.fr ‡ EA 4064, Facult´ e des sciences pharmaceutiques et biologiques, Universit´ e Paris Descartes, chan- tal.guihenneuc@parisdescartes.fr § School of Mathematical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia and Cooperative Research Centre in National Plant Biosecurity, Canberra, Australia, s.lowchoy@qut.edu.au ¶ School of Mathematical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia, k.mengersen@qut.edu.au ‖ CREST-ENSAE, 92245 Malakoff and CEREMADE, Universit´ e Paris Dauphine, Paris, France, rousseau@ceremade.dauphine.fr 2012 International Society for Bayesian Analysis DOI:10.1214/12-BA717REJ