Due to benefit ceilings, net replacement rates are lower for individuals with above-average earnings. See OECD (2007a) for full details. Across the OECD, there is significant variation in the level of support provided under the lower tier of income assistance. Due to benefit ceilings, net replacement rates are lower for individuals with above-average eamings. See OECD (2007a) for full details. In some countries, social assistance benefits are meant to prevent extreme hardship, while it is intended to minimise social exclusions elsewhere (Adema, 2006).