Model-Free and Model-Based Policy Evaluation
                 when Causality is Uncertain

                           David Bruns-Smith 1

             Abstract                 unobserved shocks are often assumed to be drawn iid ev-
   When decision-makers can directly intervene, pol-      ery period. Consider the Federal Reserve Board adjusting
   icy evaluation algorithms give valid causal esti-      monetary policy in response to oil price shocks. Events like
   mates. In off-policy evaluatio ...