There is considerable interest among companies in claiming that their products can help avoid greenhouse gas emissions compared to other products in the marketplace. While it’s true that the use of some products can help to avoid GHG emissions, accurately measuring a product’s impact—whether positive or negative—can be challenging. WRI researched existing accounting and reporting practices to identify the methodological issues critical to the relevance and credibility of comparative impact estimates. Using the research findings, this paper outlines a neutral framework for estimating and disclosing both positive and negative impacts of products and provides recommendations for companies to improve the credibility and consistency of their claims.