Outcome-based targets are needed to achieve biodiversity goals In 2010, Parties to the Convention on Biological Diversity (CBD) adopted the Strategic Plan for Biodiversity 2011–2020, and its 20 Aichi Biodiversity Targets, to catalyze national and international conservation efforts and reverse negative biodiversity trends. With the plan nearing an end, and attention turning toward a post-2020 biodiversity framework, it is timely to assess the strengths, weaknesses, and effectiveness of the Aichi Targets. Aichi Target 11, concerned with establishing effective and representative networks of protected areas (PAs) by 2020, has attracted considerable interest owing to widespread recognition of the pivotal role that appropriately situated and well-managed PAs have in conserving biodiversity ( 1 ). Substantial advances have been made toward the areal components of Aichi Target 11, with the PA estate increasing by 2.3% on land and 5.4% in the oceans since 2010 and now covering 15% of land and inland freshwater globally and 7% of the oceans ( 2 ). However, species' population abundance within and outside PAs continues to decline ( 1 ), the placement and resourcing of the majority of PAs has been poor ( 1 , 3 , 4 ), and more than half of PAs established before 1992 have suffered increasing human pressure ( 5 ). We discuss four problems with Aichi Target 11 that have contributed to its limited achievement and propose a formulation for a target for site-based conservation beyond 2020 aimed at overcoming them.