evaluation

Indicates whether CloudFormation can determine the target value, and whether the target value will change before you execute a change set.

For Static evaluations, CloudFormation can determine that the target value will change, and its value. For example, if you directly modify the InstanceType property of an EC2 instance, CloudFormation knows that this property value will change, and its value, so this is a Static evaluation.

For Dynamic evaluations, can't determine the target value because it depends on the result of an intrinsic function, such as a Ref or Fn::GetAtt intrinsic function, when the stack is updated. For example, if your template includes a reference to a resource that's conditionally recreated, the value of the reference (the physical ID of the resource) might change, depending on if the resource is recreated. If the resource is recreated, it will have a new physical ID, so all references to that resource will also be updated.