In recent years, several proposals for the design of a mechanism to reduce emissions from deforestation and forest degradation (REDD) within the United Nations Convention on Climate Change have been advanced. The essence of these proposals is to provide financial benefits to developing countries proportionally to the amount of avoided emissions they achieve, i.e. output based. A paper published in Ecological Economics [Combes Motel, P., Pirard, R., Combes, J.L. 2008. A methodology to estimate impacts of domestic policies on deforestation: Compensated Successful Efforts for "avoided deforestation" (REDD). Ecological Economics doi:10.1016/j.ecolecon.2008.06.001.] aims to provide an alternative termed Compensated Successful Efforts (CSE). It suggests that financial benefits should be provided on the basis of developing countries' successful 'efforts' to reduce emissions from deforestation, i.e. input based. The CSE approach also differs from previous ones in relation to the definition of what should be counted as avoided deforestation and how to estimate avoided deforestation. The present paper discusses the CSE approach and points out several shortcomings.