A number of policy instruments introduced simultaneously. Governments employ packages of policies for two reasons: minimization of side-effects, and uncertainty about the effects of particular policy measures. Any economic policy, such as changing the interest rate, is bound to have side-effects which are not wanted as well as the effects for whose sake the policy is adopted. The use of any single policy measure implies that it must be used strongly. This can produce significant side-effects which are both unwanted and noticeable: for example, sudden large changes in interest rates may destabilize some financial intermediaries. If several measures are used, each at a moderate level, the side-effects may be smaller and less detectable. Also, there is often uncertainty about the size and timing of the effects of particular policy measures. Use of a mixture raises the chance that at least some will produce effects fairly quickly.