We present a new static analysis method for first-class continuations that uses an effect system to classify the control domain behavior of expressions in a typed polymorphic language. We introduce two new control effects, goto and comefrom, that describe the control flow properties of expressions. An expression that does not haveagoto effect is said to be continuation following because it will always call its passed return continuation. An expression that does not haveacomefrom effect is said to be continuation discarding because it will never preserve its return continuation for later use. Unobservable control effects can be masked by the effect system. Control effect soundness theorems guarantee that the effects computed statically by the effect system are a conservative approximation of the dynamic behavior of an expression. The effect