Design tips

Evidence sources that strengthen your problem tree

A short note to deepen Lesson 1: Problem Tree Analysis.

Abayomi Ogundipe

Abayomi Ogundipe

2 min read
Evidence sources that strengthen your problem tree

A strong problem statement is not just confident language. It is evidence you can point to. The easiest way to improve your Problem Tree is to tag each branch with a source. It makes your logic visible and reduces bias.

I use this approach in my own project design work, and it helps stay aligned as the project evolves.

Here is a simple evidence checklist you can use.

Program data.

  • Attendance, completion, service usage, or wait list records
  • Even a small dataset can show a pattern over time

Community voice.

  • Quotes from interviews or focus groups
  • Notes from site visits or informal conversations

Observation.

  • What you see on the ground, logged with dates
  • This is valid evidence when it is documented

External sources.

  • Government statistics, research papers, or partner reports
  • Use one or two strong sources rather than a long list

When evidence is thin, do not hide it. Label the branch as "assumption" and plan how you will test it. That is more credible than pretending the data exists.

Quick audit: pick one branch of your tree and list two sources. If you only have internal notes, add one external source you can pull in the next two weeks. That small change will strengthen every later step.

In 🎥 Lesson 1: Problem Tree, I walk through this inside the Setup toolkit. Watch the lesson video to learn more.

Aim for at least one internal source and one external source per branch. That mix keeps the story balanced and prevents blind spots. If you only have anecdotal evidence, add a short plan to gather more data.

Diagram

Evidence Sources That Strengthen Your Problem Tree

Evidence sources that strengthen your problem tree

graph TB Branch["🌳 PROBLEM TREE BRANCH

Any cause or effect
in your analysis"] TagQ{"Does this branch
have evidence?"} subgraph Sources["📋 EVIDENCE SOURCE TYPES"] S1["📊 PROGRAM DATA

• Attendance records
• Completion rates
• Service usage
• Wait list data

Even small datasets
show patterns over time"] S2["🗣️ COMMUNITY VOICE

• Interview quotes
• Focus group notes
• Site visit observations
• Informal conversations

Direct from those affected"] S3["👁️ OBSERVATION

• What you see on the ground
• Logged with dates
• Documented consistently

Valid when recorded"] S4["📚 EXTERNAL SOURCES

• Government statistics
• Research papers
• Partner reports

1-2 strong sources
beat a long list"] end Tagged["✅ TAG AS EVIDENCE (E)

Branch is supported
by credible sources"] Assumption["⚠️ TAG AS ASSUMPTION (A)

Evidence is thin
Plan how to test it

More credible than
pretending data exists"] Balance["⚖️ EVIDENCE BALANCE

Aim for mix:
• 1 internal source
• 1 external source

Prevents blind spots"] Audit["🔍 QUICK AUDIT

Pick one branch →
List 2 sources →
If only internal notes,
add 1 external source
within 2 weeks"] Branch --> TagQ TagQ -->|Yes| Sources TagQ -->|No/Thin| Assumption S1 --> Tagged S2 --> Tagged S3 --> Tagged S4 --> Tagged Tagged --> Balance Assumption --> Balance Balance --> Audit style Branch fill:#F6F6F6,stroke:#737373,color:#2A2A2A style TagQ fill:#F8CC1B,stroke:#CA8A04,color:#2A2A2A style Sources fill:#D9F99D,stroke:#72B043,color:#2A2A2A style S1 fill:#BBF7D0,stroke:#72B043,color:#2A2A2A style S2 fill:#BBF7D0,stroke:#72B043,color:#2A2A2A style S3 fill:#BBF7D0,stroke:#72B043,color:#2A2A2A style S4 fill:#BBF7D0,stroke:#72B043,color:#2A2A2A style Tagged fill:#007F4E,stroke:#00b369,color:#fff,stroke-width:3px style Assumption fill:#F37324,stroke:#EA580C,color:#fff style Balance fill:#72B043,stroke:#5b7c37,color:#fff style Audit fill:#FEF3C7,stroke:#F8CC1B,color:#2A2A2A