protected areas are a cornerstone of conservation efforts to prevent biodiversity loss. aichi target 11 of the convention on biological diversity called for the area of protected areas to be increased to 17% of terrestrial and inland water and 10% of coastal and marine areas. it also called for those protected areas to be effectively managed, representative, and well-connected by 2020. these three qualities are crucial to conserving biodiversity within protected areas. this literature review has critically assessed the status of each of these qualities for the global protected area network. this review examined why these qualities are vital to biodiversity conservation, how they are measured, their current extent of implementation, what the gaps in the data are, and what barriers are impeding their progress. overall, studies indicate that the quality of protected areas has not kept up with the quantity. approximately one-fifth of protected areas have effective management, just over half of the protected areas could be considered connected, and approximately one-third of ecosystems have adequate representation. this is to the detriment of effective biodiversity conservation. for protected areas to realize their potential in biodiversity conservation, the qualities of the current and expanding protected area network need to be improved. it is recommended that efforts be concentrated toward increased collaboration and communication, increased financial resources, improved data quality, and the use of systematic conservation planning.