The goal of the What Works Series is to identify, review, synthesize, and share ways to overcome entrenched obstacles to improving immunization coverage and equity. We achieve this using root cause analysis and rapid evidence synthesis.  Learn more about strengthening performance accountability in our latest brief, produced by the MOMENTUM Routine Immunization Transformation and Equity project. Find the other briefs in our What Works Series, including one on revolutionizing cold chain maintenance here and addressing insufficient operational funding to reach zero-dose children and missed communities here.