5 Full-Text Review
Why Do We Review Full Texts?
Once a paper passes the title & abstract screen, the next step is to examine the entire paper to determine whether it provides usable data for our meta-analysis. This means asking:
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Does this study report a quantifiable relationship between PM₂.₅ exposure and a birth outcome?
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Is the effect estimate extractable?
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Does the study meet our core inclusion criteria?
Not all studies that sound relevant at first glance actually contain the necessary data. Full-text review helps us make that call with confidence.
What We’re Looking For
During full-text review, you’re checking for:
| Criterion | What It Means |
|---|---|
| Population | The study involves pregnant individuals (not infants or children only) |
| Exposure | PM₂.₅ or ambient air pollution exposure is measured or modeled |
| Outcome | One or more adverse birth outcomes are reported (e.g., preterm birth, low birth weight, stillbirth) |
| Effect Size | The study reports an odds ratio (OR), risk ratio (RR), hazard ratio (HR), or provides data to calculate one |
| Study Type | Observational human research (cohort, case-control, cross-sectional); not lab, review, or opinion |
| Setting | Conducted in a low- or middle-income country (LMIC), based on World Bank classifications |
Common Reasons for Exclusion
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❌ The study only looks at postnatal or child health outcomes
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❌ It focuses only on indoor air pollution without measuring PM₂.₅
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❌ It doesn’t report an effect size, or data needed to calculate one
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❌ It’s a systematic review, conference abstract, editorial, or commentary
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❌ It’s conducted in a high-income country only, unless part of a multi-country analysis that includes LMICs
What to Do When You’re Unsure
Uncertainty is normal, especially with complex or ambiguous papers. If you’re not sure:
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Leave a comment in Covidence explaining your concern
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Select “Maybe” or “Include” and flag for review
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Use keywords like missing effect size, exposure unclear, or not LMIC? to help us triage it later
We’d rather err on the side of inclusion than prematurely cut useful studies.
What Happens to Included Papers?
If a study passes full-text screening, it moves forward to data extraction—our next major step. You’ll learn how to extract adjusted odds ratios, confidence intervals, exposure windows, and more.
Tip: Keep notes as you read—some studies make extraction easier if you’ve already located the exposure and outcome info during full-text review.