UNHCR has published a comparative study of how jurisprudence has developed in the last decade in relation to the interpretation of Convention Ground "Particular Social Group": The 'Ground with the Least Clarity': A Comparative Study of Jurisprudential Developments relating to 'Membership of a Particular Social Group' and is available on the UNHCR website.
The new UNHCR publication 'Ground with the Least Clarity': A Comparative Study of Jurisprudential Developments relating to 'Membership of a Particular Social Group' is a research study which assesses jurisprudential developments in the caselaw in several key jurisdictions in the past decade. The study explores the dominant interpretative approaches of the courts and evaluates the extent to which new tests have emerged. It undertakes a critical analysis of the state of jurisprudential interpretation of Particular Social Group today. The study further examines the extent to which interpretations of the Membership of a Particular Social Group ground has evolved to meet the protection needs of emerging groups and those historically overlooked in refugee law analysis. The study draws on legislative developments and on jurisprudence at all levels in key jurisdictions, which include Australia, Canada, New Zealand, the UK, the US, Ireland, Belgium, France, Germany and Spain.
The report can be found here: http://www.unhcr.org/refworld/docid/4f7d94722.html