Conditions under which index models are useful: Reply to bio-index commentaries

This paper summarizes the key conditions under which the index method is valuable for forecasting and describes the procedures one should use when developing index models. The paper also addresses the specific concern of selecting inferior candidates when using the bio-index as a nomination helper. Political decision-makers should not use the bio-index as a stand-alone method but should combine forecasts from a variety of different methods that draw upon different information.