This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Research Methodology is the study of how a systematic inquiry should itself be designed and conducted, its method the evaluation and design of the procedures, controls and analyses by which a claim is tested rather than of any one subject matter itself. The field's foundational text is Ronald Fisher's 1935 book The Design of Experiments, which set out the principles of controlled experimental design still used across the sciences today.
For an atlas of religion and belief, research methodology underlies the account, given elsewhere in this collection, of how a scholarly claim about religion was actually tested, whether that claim concerns a historical event, a psychological experience or a population's inherited ancestry. Fisher's own principles of controlled design, sampling and analysis are what separate a study that genuinely tested a claim about religion from one that merely restated it.
That separation is why the field matters here specifically. Every discipline this atlas draws on to test a religious claim, archaeology's stratigraphy, history's source criticism, genetics' population analysis, psychology's controlled experiment, depends on research methodology's own principles to say whether the test itself was sound.