Abstract
Government population projections are typically underpinned by a set of assumptions based on what has happened in the past, informed by expert opinion on what the future holds. The assumptions made are inevitably subject to uncertainty e.g. trends may change unexpectedly. This seminar considers sources of uncertainty in recent population projections for Northern Ireland and the Republic of Ireland, both national and sub-national. Past experience with population projections is examined to illustrate the effects of changing trends and economic circumstances. The seminar then looks at sources of uncertainty in the most recent 2006-based projections. The concluding remarks discuss the management of uncertainty.