Disentangling family socioeconomic components, candidate processes, and preschool cognitive outcomes: A systematic scoping review, evidence map, and source-audited direction synthesis.

Family socioeconomic indicators are often combined despite capturing partly distinct aspects of family circumstances. We conducted a systematic scoping review and evidence map of parental education, family economic background, composite socioeconomic status, and preschool cognitive outcomes. Report-level mapping covered all component-domain combinations, whereas source-verified direction and magnitude synthesis was restricted to the two largest component-specific language/literacy cells. Four databases were searched through May 20, 2026. After deduplication and screening, 217 reports were included. Full-text verification yielded 51 report × cell effects and 48 overlap-controlled independent units from 41 reports. In the parental-education/language cell, 19 of 32 units were positive and statistically supported; in the economic-background/language cell, 6 of 16 were positive and statistically supported. Across both cells, 39 of 48 units were positive in direction, but only 25 met the prespecified statistical-support criterion; the remaining evidence included unsupported or attenuated findings, insufficient uncertainty information, and model-dependent or conditional patterns. Nineteen of 29 co-measurement reports used conventional same-model mutual adjustment. No metric family met criteria for a defensible pooled meta-analysis because of heterogeneity in constructs, metrics, models, measurement, and uncertainty reporting. Overall, the findings motivate a component × domain × process framework as a hypothesis-generating research architecture: socioeconomic components are related starting conditions, cognitive outcomes are domain-specific endpoints, and proximal family or educational variables remain candidate processes requiring direct testing rather than established mechanisms.