OmniGOV@MGOMD was established to be the world’s best government media buying service and deliver better outcomes for UK government departments and related arms-length bodies. As part of a broad push to instil an effectiveness culture across multiple teams, a database of effectiveness benchmarks was created for government paid-for media campaigns. It has been used to guide marketers and agencies to make better decisions in campaigns of different types and budgets. This case presents evidence this work has led to a variety of better outcomes and communications now ranks among the most accountable forms of investment made by UK government.