This project willl investigate the effect of the Peruvian land titling program on the use of the remaining common resources in rural highland communities. The Special Land Titling and Cadastre Project (PETT) in Peru has over the last decade issued titles for over 5.8 million agricultural plots, unique in the world when it comes to the extent and speed of the process.In addition to agricultural land, communities in the Peruvian highlands hold forest land, grazing areas and unproductive mountainous areas. These lands are vulnerable to degradation as an effect of over-exploitation, soil-erosion and drought, with increased urgency due to climate change. Sustainable management of common resources requires cooperation between individuals and household. Land t itling might make individual farmers less dependent on the goodwill of their community and their leader, which decrease incentives for cooperation within the community. The main purpose of the project is to investigate whether a result of land titling in the Peruvian highlands is less cooperation on common natural resources within communities. Women empowerment might be an important side-effect of the PETT program, as there has been a large rate of joint titling to both spouses in parts of the implement ation. The project will investigate whether this has made decision-making within households and communities more equal regarding gender, and whether any such shift in bargaining-power might change the way common resources are managed and used.A special feature of the PETT program is that the implementation of the land titing process have been to some extent random, which opens possibilities to analyse it as a natural experiments and thus gaining imporant causal mechanisms.The project will start by ana lysing qualitative and quantitative data on land issues from the specific area, which will be used to design proper experiments to be run in the field, to test the hypotheses.