Over the past decade, think tanks and other organizations that advocate for charter schools have published a series of publications that purport to show large funding disparities between charter and district public schools, to the detriment of charter schools. These reports all tend to suffer from similar flaws in methodology—flaws that are significant enough to render their conclusions invalid. Charter schools have grown significantly within the past several years, and policy around them has important consequences. Diverting more funding toward them based on unsound research could have real and pernicious effects on district schools and state budgets. Disparate third-party reviewers have repeatedly pointed out problems, yet there appears to be little or no willingness to move away from the flawed approaches, which continue to plague report after report. This policy memo illustrates these problems with a focus on one of the latest of the “charter school funding inequity” reports, and provides a guide for stakeholders to evaluate the accuracy and transparency of research.