| Screening accuracy & PRISMA discipline | Applies the explicit PICO + RCT-only criteria correctly: includes exactly the eligible RCTs and excludes the rest, each with the correct concrete reason (wrong design, population, comparator, or outcome not reported), and reports coherent PRISMA identification/screening/eligibility/included counts. | Includes ineligible studies (e.g. the observational cohort, the VTE/valve populations, the placebo/aspirin or DOAC-vs-DOAC comparators, or the study that doesn't report the outcome), drops eligible RCTs, or gives no/garbled PRISMA flow. |
| Effect-measure & log-scale handling | Uses the correct measure (OR for efficacy, RR for safety), pools on the LOG scale, and derives each study's SE from its CI as (ln(hi)-ln(lo))/(2*1.96) rather than treating the point estimate or CI on the natural scale. | Pools raw (non-log) ratios, mishandles or invents the standard errors, mixes OR and RR, or pulls the wrong outcome's effect for a study. |
| Pooling-model choice & I^2 interpretation | Computes Cochran's Q and I^2, and chooses fixed vs random-effects coherently with the heterogeneity (I^2>50% => random-effects), naming the DerSimonian-Laird estimator and interpreting I^2 correctly. | Ignores heterogeneity, picks a fixed-effect model despite high I^2 (or vice versa with no rationale), or misreads what I^2 means. |
| Numerical correctness of the pooled estimate & CI | The pooled point estimate, 95% CI, and I^2 match the deterministic inverse-variance / DerSimonian-Laird computation within rounding, and the pooled estimate sits within the range of the included study estimates. | Pooled estimate or CI is materially wrong, falls outside the plausible range of inputs, has an inverted/implausible CI, or the arithmetic is unjustified. |
| Evidence faithfulness | Every study, effect estimate, and CI used traces to the actual tool outputs; no fabricated trials, effects, or CIs, and excluded studies' numbers are not smuggled into the pool. | Fabricates studies or effect sizes, alters the reported CIs, or pools effects from studies it claimed to exclude. |