The side-effects model considers such unintended side-effects while retaining the focus on goals similar to the goal-attainment model. The side-effects model does this by looking for side-effects beyond the ‘target area’ of the policy intervention. A side effect in this case can be defined as “at least a partial consequence of the intervention, which cannot be included among the desired main effects, and these can be unanticipated, anticipated, beneficial or detrimental and considered in calculations preceding decisions to adopt policies” (Vedung, 2013). Within the target area the policy intervention can also generate impacts that are contrary to what was intended (‘perverse effects’). A challenge for the evaluators in the case of side-effects is to determine how to value or place these side-effects in the overall evaluation of the policy intervention, given these were not anticipated.