According to the OECD, basic income (BI) is not an effective tool for reducing poverty. However, the outcome would depend on the model chosen for implementing a BI system, as well as the changes made in other parts of social protection.
Most people with a basic income will live a lot like they do now. They will have a more stable income. They will worry less about many of their friends and family. This cuts into the number of people who would choose the couch.