In the persuasion model, apart from a few special cases, comparative statics has been an open question. We answer it, delineating which shifts of the sender's interim payoff lead her optimally to choose a more informative signal. Our first theorem identifies a coarse notion of 'increased convexity' that we show characterises those shifts of the sender's interim payoff that lead her optimally to choose no less informative signals. To strengthen this conclusion to 'more informative' requires further assumptions: our second theorem identifies the necessary and sufficient condition on the sender's interim payoff, which strictly generalises the convex-concave ('S') shape commonly imposed in the literature. We identify conditions under which increased alignment of interests between sender and receiver leads to comparative statics, and study a number of applications.
Comparative Statics of Information Acquisition and Risk Aversion
Universidad Carlos III（卡洛斯三世大学）；University of Mannheim（曼海姆大学）；CNRS – École Polytechnique（法国国家科学研究中心-巴黎综合理工学院）；Department of Mathematics, London School of Economics（伦敦政治经济学院数学系）；Brown University（布朗大学）
Department of Managerial Economics and Strategy, London School of Economics（伦敦政治经济学院管理经济学与战略系）；Department of Economics, National University of Singapore（新加坡国立大学经济学系）
