(April 2015) – This briefing paper reviews the international research literature on the effectiveness of border control policies – particularly immigration detention – in reducing irregular migration. The brief argues that detention is not only ineffective at reducing irregular migration to desired levels, but also weakens other migration management outcomes such as case resolution, departure for refused cases and integration for approved cases. Given these weaknesses, governments would be better placed prioritizing alternatives to detention. The brief further shows policy development and targeted resource allocation could improve the prospects of migrants by increasing avenues for legal migration and improving life chances in countries of origin and transit. The brief shows destination countries must consider big picture, multi-layered responses to address root causes of irregular movement and reduce the pressures on migrants to undertake risky journeys in an irregular manner.