Weak signals
A common name, approximate age or large city is rarely conclusive alone. Do not combine records merely because they look similar. First determine whether a more specific shared detail is present.
Independent support
Compare information that actually comes from different sources. A repeated record across several places may be copied. Identical wording and identical errors are reasons to examine provenance.
Keep contradictions visible
Different dates or incompatible details matter as much as matches. Record the discrepancy rather than choosing a version without justification. Keep records separate when a conflict cannot be explained.