File-drawer tests assume uncovered unpublished studies form a random sample.

Evidence

This method also makes a critical assumption, namely, that the unpublished studies that we uncovered constitute a random sample of unpublished research on the topic. For this and other reasons, the power of this direct approach, as Begg (1994) noted, is “directly proportional to the assiduousness of the search” (p. 405). Thus, we expended great effort in obtaining as many unpublished manuscripts as possible. We uncovered 88 unpublished contact studies, 70% of which are graduate dissertations. — Thomas F. Pettigrew, Linda R. Tropp, A Meta-Analytic Test of Intergroup…, 50

Categorization

• XREF: Ties to meta-analysis methodology and the reproducibility debate; echoes issues raised around publication bias across disciplines.

Related

• A meta-analysis synthesized 515 studies with 250,089 participants across 38 nations. (similarity 0.80)
• Meta-analyses overestimate effect sizes because null results go unpublished. (similarity 0.80)
• The intergroup contact-prejudice link survives file-drawer checks, indicating limited publication bias. (similarity 0.78)