claude-plugins/genealogy/skills/genealogy-methodology/references/evidence-evaluation.md

Evidence Evaluation and Conflict Resolution

Detailed frameworks for analyzing genealogical evidence, resolving conflicts between sources, and building proof arguments.

Source Weighting

Not all sources are equal. When sources conflict, weight them — don't count them.

Weighting Factors (in priority order)

1. Proximity to event — Was the informant present? Was the record created at the time of the event?
2. Informant knowledge — Did the informant have direct knowledge, or are they reporting hearsay?
3. Purpose of the record — Was the information central to the record's purpose (bride's name on a marriage license) or incidental (birthplace on a census)?
4. Original vs. derivative — Are you looking at the original, or a transcription/abstract that may contain copying errors?
5. Internal consistency — Does the source contradict itself?
6. Corroboration — Do independent sources agree? (Derivative copies of the same original are NOT independent corroboration.)

Common Weighting Mistakes

• Counting sources instead of weighing them. Three Ancestry member trees copying the same wrong date don't outweigh one original record.
• Treating indexes as sources. An index points to a record. The record is the source. Index errors are common.
• Assuming original = accurate. A death certificate is an original source but contains secondary information about birth (reported decades later by someone who may not have been present).
• Ignoring negative evidence. A person's absence from a record they should appear in is evidence. It doesn't prove anything alone, but it contributes to the picture.

Conflict Resolution Framework

When sources disagree about a fact:

Step 1: Define the Conflict Precisely

State exactly what each source says. "The birth year is unclear" is not precise. "The 1850 census says age 35 (born ~1815), the 1860 census says age 50 (born ~1810), and the death certificate says born 1812" is precise.

Step 2: Classify Each Source

For each conflicting source, document:

• Source type (original / derivative / authored)
• Information type (primary / secondary / undetermined)
• Evidence type (direct / indirect / negative)
• Informant (who provided the information, if known)
• Informant's relationship to the fact (direct knowledge / hearsay / unknown)

Step 3: Identify Explanations

Before choosing a winner, consider why the sources disagree:

• Transcription error — The original says one thing, the copy says another
• Informant error — The person reporting didn't know or misremembered
• Different informants — Each source had a different informant with different knowledge
• Rounding or estimation — Census ages are often rounded; "about 35" could mean 33-37
• Identity confusion — The sources may be about different people with the same name
• Both partially correct — The truth may be between the sources (e.g., moved mid-year)

Step 4: Apply Evidence Weight

Rank the sources from most to least reliable for THIS SPECIFIC FACT. A source can be highly reliable for one fact and unreliable for another within the same document.

Step 5: State the Conclusion

• If one source clearly outweighs others: state the conclusion and explain why
• If sources are roughly equal: acknowledge the conflict is unresolvable with current evidence and note what additional records might resolve it
• If a pattern emerges (e.g., ages consistently decrease on later censuses): note the pattern as it may explain the discrepancy

GPS Deep Dive

Element 1: Reasonably Exhaustive Research

"Reasonably exhaustive" does not mean "every record ever created." It means:

• You searched the record types that could confirm or deny the claim
• You searched the repositories where those records are likely held
• You searched for the subject AND relevant FAN members
• You documented what you searched, including negative results
• You did not stop at the first confirming source

Test: Could a competent researcher point to an obvious, accessible record set you didn't check?

Element 2: Complete and Accurate Citations

Every source must be cited with enough detail that another researcher can:

• Find the exact same record
• Evaluate the source's reliability
• Distinguish between the original record and the access method (e.g., "digital image of original" vs. "database entry")

Element 3: Analysis and Correlation

Sources must be compared to each other:

• What do they agree on?
• What do they disagree on?
• Do they corroborate independently, or are they derivative of each other?
• What does each source contribute to the overall picture?

Element 4: Resolution of Conflicting Evidence

Conflicts cannot be ignored. For each conflict:

• Acknowledge it explicitly
• Explain possible causes
• Apply evidence weight
• State whether the conflict is resolved or remains open
• If unresolved, explain what additional evidence might resolve it

Element 5: Soundly Reasoned Conclusion

The conclusion must:

• Follow logically from the evidence presented
• Not overstate what the evidence supports
• Acknowledge limitations and remaining uncertainties
• Be written clearly enough that another researcher can follow the reasoning and evaluate it independently

Proof Levels

Level	Meaning	GPS Status
Proven	Beyond reasonable doubt	All 5 elements fully satisfied
Probable	Preponderance supports it	Most elements satisfied; minor gaps
Possible	Some evidence supports it	Significant gaps in research or evidence
Unproven	Insufficient evidence	Cannot assess; more research needed
Disproven	Evidence contradicts it	Evidence actively refutes the claim

Common Genealogical Evidence Patterns

Census Age Discrepancies

Census ages are notoriously unreliable. The informant may not have known exact ages, may have rounded, or the enumerator may have estimated. A 2-3 year spread across censuses is normal and does not constitute a meaningful conflict.

Name Spelling Variations

Before standardized spelling, names were recorded phonetically by the recorder. Atreides/Atreidies, Halleck/Hallek/Hallak, Leto/Leeto are the same name. Treat spelling as fluid, not as evidence of different people.

"Same Name, Same Place" Trap

Two people with the same name in the same county are NOT necessarily the same person. Use age, associates, property, and family context to distinguish. The existence of "Sr." and "Jr." designations in records may indicate father/son, but may also just mean "older" and "younger" among unrelated men.