This report assesses whether the United States Global Change Research Program's draft Climate Science Special Report (CSSR), a technical report that details the current state-of-science relating to climate change and its physical impacts, accurately presents the scientific literature in an understandable, transparent and traceable way; whether the CSSR authors handled the data, analyses, and statistical approaches in an appropriate manner; and the effectiveness of the report in conveying the information clearly for the intended audience. This report provides recommendations for how the draft CSSR could be strengthened.