Studying only surviving religions introduces survivor bias

Evidence

This cultural winnowing of religions over time is evident throughout history and is occurring every day. It is easy to miss this dynamic process, because the enduring religious movements are all that we often see in the present. However, this would be an error. It is called survivor bias. When groups, entities, or persons undergo a process of competition and selective retention, we see abundant cases of those that “survived” the competition process; the cases that did not survive and flourish are buried in the dark recesses of the past, and are overlooked. To understand how religions propagate, we of course want to put the successful religions under the microscope; but we do not want to forget the unsuccessful ones that did not make it—the reasons for their failures can be equally instructive. — Norenzayan, Ara, Big gods - how religion transformed…, 27

Categorization

• XREF: Names ‘survivor bias’ explicitly — the methodological trap the reader’s own cross-source integration (big gods vs. fumi-e) must avoid when generalizing from Christianity.