This document provides methodology details for the 2018 Edelman Trust Barometer survey. It describes the online survey conducted in 28 markets with over 33,000 total respondents. The general population sample included 1,150 respondents per market ages 18+, while the informed public sample included 500 respondents in the US and China and 200 in other markets who met certain criteria. Response margins of error are provided for each sample group. The document outlines the methodology used to measure trust in key institutions and trends in trust over time.