Health impact assessment: a tool for healthy public policy.

Healthy Public Policy is one of the key health promotion actions. Advancement of Healthy Public Policy requires that the health consequences of policy should be correctly foreseen and that the policy process should be influenced so that those health consequences are considered. Health Impact Assessment is an approach that could assist in meeting both requirements. Policies often produce health impacts by multiple indirect routes, which makes prediction difficult. Prediction in Health Impact Assessment may be based on epidemiological models or on sociological disciplines. Health Impact Assessment must be based on an understanding of, and aim to add value to, the policy-making process. It must therefore conform to policy-making timetables, present information in a form that is policy relevant and fit the administrative structures of policy makers. Health Impact Assessment may be used to inform health advocacy but is distinct from it. There is a danger that Health Impact Assessment could be misunderstood as health imperialism.