The Tree Health Assessment Tool helps you examine and document the strength of evidence for each conclusion in your family tree. In my previous article, I explained why this systematic approach is essential for building accurate family history. This article provides step-by-step instructions for implementing the tool in your research.
The Tree Health Assessment Tool uses a simple color-coding system to evaluate evidence strength: green for strong evidence, yellow for insufficient evidence requiring more research, and red for absent or inadequate evidence.
This post was originally published in January 2022 and last updated on 23 June 2025
How to Evaluate the Evidence
Family history interprets historical documents and other sources such as DNA test results to reach conclusions about the past. These conclusions are based on evidence. A conclusion is considered reasonable and defensible if it is based on strong evidence.
Just adding source citations to a conclusion is not sufficient to indicate the strength of the evidence, because it is not possible to judge the evidence from those citations. Additional documentation is needed. That is where the Tree Health Assessment Tool comes in.
Tips for Evaluating Evidence
Evaluating evidence is a complex topic, but for the purposes of using the Tree Health Assessment Tool, here are the key things to keep in mind.
Your evidence is not strong enough to be green if you have:
a) no source citations — colour it red or leave it uncoloured
b) just one source citation — colour it yellow or red depending on the quality of the evidence provided by that source
c) just indirect evidence — colour it yellow or red depending on the quality of the evidence provided by the sources you have.
Your conclusion may be green even if you have just one documentary source or indirect evidence (situations b and c), if you also have DNA evidence that supports the conclusion.
Quick Decision Rules:
- If you’re unsure between yellow and red, choose red – it’s better to be conservative
- When in doubt, gather more evidence before moving to green
- Remember: independent sources are created for different purposes with information supplied by different informants.
Conduct a Tree Health Assessment on Your Direct Line
Evaluate the first three generations of your direct line ancestors to confirm that your family history has a solid foundation.
You can extend the chart beyond these generations if you have evidence for them. Or you can leave that until you are researching a particular family line.
Step 1: Create an Evidence Table for Your Direct Line
The tree chart provides the visual representation of the health of your family tree, but you also need to document the evidence that supports the results. Do this in an evidence table.
Create a table with six columns, plus headings:
- Person’s name
- Relationship
- Evidence source 1
- Evidence source 2
- Evidence level (Sufficient: Green, Insufficient: Yellow, None: Red, Not researched: blank)
- Notes
Add your family to the rows in column 1:
- parents
- four grandparents
- eight great grandparents.
Step 2: List and Evaluate the Evidence
For each person, list the best evidence you have to support their identity and relationship to the child who is your direct ancestor. The evidence in columns 3 and 4 must be independent of each other.
Remember: Independent sources are created for different purposes with information supplied by different informants.
Important: Do not do this analysis from memory and do not base your evaluation purely on the existence of source citations. Examine the actual sources and the evidence they contain. Note any inconsistencies.
Evaluate whether the evidence is sufficient to support your conclusion and mark column 5 with the colour that represents the level of evidence.
Step 3: Create a Family Tree Chart
Now create a family tree chart to illustrate the results of your tree health assessment.
Create an ancestry chart which includes the people in the table from Step 1.
You can create your chart on paper if you wish, but a digital copy is usually best for storage purposes. Use any program that allows you to add coloured lines, such as PowerPoint, Word or Excel.
Use the information from column 5 of the evidence table to colour the lines of your family tree chart:
- Green lines for sufficient evidence
- Yellow lines for insufficient evidence
- Red lines for no evidence or serious concerns
Conduct a More Detailed Tree Health Assessment
The Tree Health Assessment Tool for your direct line operates at a high level, by just examining the evidence for the identity of a person and their relationship to their parents and children. This is essential, but it is not enough for an accurate family history.
Conduct a more detailed assessment to examine the strength of the evidence for other conclusions.
Assess a Family Group
Apply the Tree Health Assessment to each person in a family group and document the results on family group sheets.
In this assessment you evaluate the evidence for each of the conclusions listed on the sheet, such as:
- The identity of the parents of the couple
- Birth dates and places
- Marriage dates and places
- Death dates and places
- The identity of a couple’s children, and their vital details.
For example, the evidence for the marriage may be green and the evidence for the birth may be yellow.
There are tons of Family Group sheets available for download online.
A Comprehensive Tree Health Assessment
Use a comprehensive Tree Health Assessment to evaluate and document the strength of evidence for your entire family tree. I only include the family groups on my direct line, but you could also include other family groups.
Select a set of conclusions to evaluate for each generation. You need events that most family groups experience, as each event is documented in the column of a table. I use the ones listed above for individual family group assessments. I add a few more, such as when the individuals migrated to Australia.
Record your assessment in a table. Excel, or similar spreadsheet program, is best as you can use the filtering functions to make the large dataset more manageable. However, you could also create one in another program such as Word.
This table is similar to the evidence table for your direct line, except:
- Each row is a family group on your direct line
- You have a column for each event or conclusion.
The sufficiency or strength of the evidence is indicated by the colour in the cell which is the intersect between the family row and the event column. You don’t need a separate column for the evidence level.
Use the Results of the Tree Health Assessment in Your Research
The Tree Health Assessment Tool supports your research at every step of the research process. Here are some examples.
Plan Your Research, Establish Goals and Create Research Questions
Use the results of a Tree Health Assessment to inform your research goals and identify new research questions:
Work from the ‘known’, which is represented by green, to the ‘unknown’, which is represented by yellow. Create specific research questions targeting these points.
Do not research a new generation until the previous generation has a substantial amount of green in a comprehensive assessment.
Identify Research Tasks
Use the Tree Health Assessment to identify specific tasks for each research question, to gather the evidence needed to turn yellow to green, and red to yellow. Update your research plan.
Example task: Obtain a copy of the original baptism record to corroborate the date of birth and provide independent evidence.
Document Evidence
Update your family tree to indicate the strength of the evidence for your conclusions. Add any new evidence as it is gathered.
Most family history software and online family trees are not designed to document the strength of evidence. Wikitree is an exception. It allows you to select the level of confidence for conclusions.
You could add tags or hashtags to your family tree, to indicate which people need more evidence. And you could also document the evidence as research notes.
You could also include the results of a Tree Health Assessment in an evidence summary or evidence argument (aka ‘proof summary’ and ‘proof argument’).
Review Your Research or Someone Else’s Research
A Tree Health Assessment should become a standard step when you are reviewing your family history for any reason. It provides essential information that will impact on decisions about the accuracy of your family history, whether you have conducted a reasonably exhaustive search and used the best sources available.
You can also use the tool to analyse the accuracy of someone else’s family tree. Use it to review:
- research passed to you by a family member
- an online family tree, before you use their conclusions as a research lead for your own research
- the family tree of a DNA match to verify your common ancestors.
Take Action with Your Tree Health Assessment
The Tree Health Assessment Tool transforms abstract concepts about evidence quality into concrete, actionable steps. By systematically evaluating your family tree’s foundation, you’ll spend your research time more effectively and build a more accurate family history.
Start with your direct line assessment. Focus on those first three generations that form your family tree’s foundation. Once you see the gaps and strengths clearly marked in green, yellow, and red, you’ll know exactly where to direct your research efforts next.
More information
For more articles and information about this tool, head to the Tree Health Assessment Tool page. You can also download your free copy of the THA Tool guide on my Free Stuff page.
For more of my articles about analysing sources, go to the Analyse page.
About the Author
Danielle Lautrec is a genealogy educator, researcher, and author of The Good Genealogist. With qualifications in history, family history, and historical archaeology, she teaches for the Society of Australian Genealogists.
5 thoughts on “How to Apply the Family Tree Health Assessment Tool”