Making Sample Adequacy Assessable: A Systematic Review of Saturation Reporting and Other Adequacy Rationales in Qualitative Gig-Worker Research

Qualitative studies may report saturation without specifying what was judged sufficient, supporting evidence, or scope. This systematic review examines how studies of gig-worker experiences report saturation and other sample-adequacy rationales. Searches of Scopus and Web of Science yielded 343 records. After screening 237 deduplicated records and assessing 159 full texts, 44 studies reporting an adequacy rationale were included. Thirty-two specified an operational saturation criterion, such as no new themes or concepts; 12 presented limited or general claims, literature-based sample-size justification, or alternative rationales. Eight of the 32 operational saturation studies reported saturation judgments at specified interview counts ranging from 7 to 51, across different sampling scopes and analytic aims. Study-level coding of the 32 operational studies, informed by the methodological literature, yielded six reporting dimensions: adequacy logic, analytic object, sampling boundary, monitoring process, confirmation evidence, and bounded claim. Among these, 31 reported monitoring, nine explicit confirmation evidence, and two explicitly bounded claims. The framework offers authors and reviewers a structured way to examine how published reports connect adequacy criteria, supporting evidence, and the scope of their claims. The findings describe studies reporting an adequacy rationale and do not estimate reporting prevalence across all qualitative gig-work research.