We derive the analogue of the classic Arrow-Pratt approximation of the certainty equivalent under model uncertainty as defined by the smooth model of decision making under ambiguity of Klibanoff, Marinacci and Mukerji (2005). We study its scope via a portfolio allocation exercise that delivers a...

We study orders of risk and model uncertainty aversion in the smooth ambiguity model proposed by Klibanoff, Marinacci, and Mukerji (2005). We consider a quadratic approximation of their model and we show that both risk and model uncertainty attitudes have at most a second order effect....