What Are The Odds (WATO)

Test genealogical placement hypotheses for an unknown person or mystery match against known DNA amounts. Open this screen when you want to determine where an unidentified ancestor or unknown DNA match fits into an existing family tree.

What you see

The Scenario label field allows you to name the current investigation scenario.

The Testers area includes an Add a tester person selector and lists selected individuals from your tree along with Remove buttons.

The Hypotheses section contains cards for each placement hypothesis with fields for Label, Common ancestor family id, and Generations below, followed by an Add hypothesis button.

The Save and compute button saves the scenario configuration and calculates odds ratios.

The Results table displays computed scores with columns for Hypothesis, Combined likelihood, Odds vs. second best, and a qualitative assessment under Read.

Common tasks

Define a placement scenario

1. Enter a descriptive title in the Scenario label field.
2. Select Add a tester to choose known relatives from your tree who share DNA with the mystery kit.
3. Select Add hypothesis to define a potential placement in the pedigree.
4. Enter the description in Label, the corresponding family ID in Common ancestor family id, and the generational distance in Generations below.

The scenario builder holds your testers and candidate positions.

Calculate and compare hypothesis odds

1. Ensure all testers and hypotheses are configured in the scenario.
2. Select Save and compute.

The Results table populates with combined likelihood values and relative odds rankings for each candidate placement.

Remove a tester from a scenario

1. Locate the tester in the Testers list.
2. Select Remove next to their name.
3. Select Save and compute to recalculate the scenario scores.

The results update to reflect the revised tester group.

Good to know

• The calculation uses Christopher Larkin's WATO methodology to determine combined likelihoods across multiple testers.
• Odds ratios of 10 to 1 or higher indicate strong statistical support for a hypothesis relative to the next best alternative.