The increasing demand for using environmental valuation results in a policy context implies that it becomes increasingly important that those results are reliable. A few years ago, the Swedish Environmental Protection Agency concluded that there is a need for tools that enable assessments of the quality of valuation studies and initiated the development of a quality assessment instrument (QAI). The result was a QAI that aims at being based on objectively observable study characteristics as far as possible. The QAI is based on the identification of a number of quality factors, each of which is in turn made concrete by at least one check question to be answered by “yes”, “no”, “don’t know” or by a piece of information about the study being assessed. The paper presents the QAI by applying it to two Swedish valuation studies on forest issues. It also discusses some of the difficulties associated with quality assessments.