Ad Fontes Media, Inc. is a media watchdog organization based in Colorado that is best known for its Media Bias Chart, which ranks media sources based on political bias and reliability. We combine their ratings of individual articles and episodes to create a weighted average, with low-rated items increasingly weighted higher.

Media Bias/Fact Check (MBFC) is an American fact-checking website founded in 2015. It uses a 0-10 scale to rate sites on two areas: bias and factual accuracy. A source rated by MBFC with minimal bias gets 10 plus points. Maximum bias gets 10 minus points. The same principle applies to factual accuracy.

Press councils are national institutions of media self-regulation. Press councils have their own defined press code. Reprimands are issued in the event of a violation of the press code (e.g. for truthfulness, diligence, sensationalism, separation of advertising and editorial, personal rights). For each reprimand issued by a national press council, a source receives one minus point.

We primarily use fact-checkers affiliated with the International Fact-Checking Network (IFCN). We have linked to the International Fact-Checking Network fact-checkers' code of principles in the headline. For each failed fact-checker there is one minus point.

Wikipedia's reliability was often criticized in the 2000s but has improved over time; in the late 2010s and early 2020s, it was universally praised. Any positive mention of a source in the extract of a Wikipedia page in terms of credibility and quality gets a plus point, and vice versa.

Journalism prizes are awards for excellent journalistic work in the period covered by the call for entries, which is usually one or two years. Sources receive one plus point for each journalistic award won that we track. We currently track up to three prestigious awards per country.

Most scientific publications, though not all, rely on some form of peer review or editorial review to qualify texts for publication. Sources mentioned in studies which rate media quality and/or reliability receive between 10 plus and 10 minus points.