Literature Synthesis (ppsych-literature-synthesis)

When to trigger

• The topic/proposal is set and it is time to read across the relevant sub-areas thoroughly
• Reading feels unsystematic; you fear missing work a psychologist from an adjacent area would expect
• You have many papers but no way to weigh, compare, or reconcile their findings across paradigms
• For meta-science: you need systematic evidence about the field's practices, not just substantive findings

Coverage discipline: read across areas, not one literature

A PoPS piece's credibility rests on the reader's belief that you read across the relevant sub-areas, not only your home paradigm — and PoPS reviewers are often drawn from the very areas being integrated, so siloing is noticed. Build coverage systematically:

1. Seed set. Start from the proposal's key references and each sub-area's canonical pieces.
2. Forward + backward snowball. Backward: every paper's reference list. Forward: who cites the seeds (Google Scholar / Scopus / Web of Science). Iterate until new searches stop turning up unseen important work (saturation).
3. Database + keyword sweep. Search PsycINFO/APA PsycNet, plus PubMed and discipline databases for adjacent fields (neuroscience, methods), by topic keywords and by the terms each sub-area uses for the same construct — different areas name the same phenomenon differently.
4. Preprints + adjacent fields. A current PoPS piece must include recent preprints (PsyArXiv) and the bordering literatures the argument draws on, or referees flag staleness and siloing.
5. Saturation log. Record when each sub-area's search stops yielding new must-cite work — your evidence of comprehensiveness for ppsych-comprehensiveness-and-balance.

Meta-science: systematic evidence about the field's practices

If the piece is meta-science (about replication, reporting, power, bias, or methods as practiced), the "literature" includes the field's outputs as data: prevalence of a practice, distributions of statistics, registered-report rates, sharing rates. Treat the search as a systematic protocol:

• Pre-specify the sampling frame (journals, years, article filter) and inclusion/exclusion rules — ideally preregistered (see ppsych-transparency-and-reproducibility).
• Pilot and document the coding scheme (what counts as a preregistration, an open-data badge, an underpowered design).
• Report search dates, hit counts, and screening outcomes (a PRISMA-style flow) so a reader can audit the corpus.
• Plan double-coding and inter-rater reliability for any subjective extraction.

From reading to synthesis (not summary)

Summarizing restates each paper; synthesizing makes papers from different areas talk to each other. Maintain an evidence matrix:

This matrix feeds the organizing framework, the summary exhibits, and the even-handed treatment of controversies. You appraise the primary work; you do not re-run it (unless the piece is a meta-analysis with a superordinate message — then its data/code must be reproducible).

Checklist

• Seed set drawn from each sub-area's canonical pieces + proposal references
• Forward and backward snowball iterated to saturation in every sub-area
• PsycINFO/PsycNet + adjacent databases swept by keyword and each area's construct terms
• Recent preprints (PsyArXiv) and bordering literatures included (no staleness, no silo)
• Saturation log records where each area's searches stopped yielding new must-cites
• Meta-science: sampling frame + coding scheme pre-specified (ideally preregistered); PRISMA-style flow
• Evidence matrix captures construct + method + finding + credibility + cross-area tension
• Non-comparable constructs flagged as such (not pooled into a false "the literature finds…")

Anti-patterns

• Citing from one's home paradigm only (predictable cross-area gaps the integrated areas will spot)
• Summarizing paper-by-paper instead of synthesizing across areas
• Pooling studies that measure different constructs into one "the field finds…" claim
• Ignoring preprints (looks stale) or adjacent fields (looks siloed) in a broad journal
• Meta-science with an undocumented, unreplicable search — the reform critique applies to your own piece
• Re-running or "correcting" primary studies in a non-meta-analytic review — you appraise, you don't re-estimate

Output format

【Seed set】<canonical pieces per sub-area + proposal references>
【Snowball status】backward/forward iterated to saturation across areas? Y/N
【Databases swept】PsycINFO/PsycNet + adjacent — by keyword + construct terms? Y/N
【Preprints + adjacency】PsyArXiv + bordering literatures included? Y/N
【Meta-science protocol】sampling frame + coding scheme pre-specified; PRISMA flow? Y/N · N/A
【Saturation evidence】<where searches stopped yielding new must-cites>
【Evidence matrix】rows ready with construct / method / finding / appraisal / tension? Y/N
【Coverage risks】<any area/author an omission referee could name>
【Next step】→ ppsych-organizing-framework (impose the analytical spine on the matrix)