Assumptions you should write down

Every project has assumptions. The difference is whether you write them down.

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

Assumptions are the conditions that must be true for your Theory of Change to work. If you do not name them, you cannot test them. That is a risk.

Here are common assumptions worth listing:

The community will participate if invited
Local leadership will allow program access
The proposed activity fits the school or work calendar
Key staff will remain in place during delivery

A simple way to capture assumptions is to add a small box next to each link in your Theory of Change:

Activity -> Output: What must be true?
Output -> Outcome: What must change in behavior?
Outcome -> Impact: What must stay stable?

Then mark each assumption as one of three types:

Testable now (you can validate in the next month)
Testable later (requires time or data)
Outside your control (needs a mitigation plan)

Try this: pick one assumption and list one way to test it. If you cannot test it, write a mitigation step instead. This keeps your plan realistic.

In Lesson 4 🎥, I walk through this inside the toolkit. Watch the lesson video to learn more.

Once you list assumptions, rank them by risk. High risk and low evidence assumptions should be tested first. This turns your ToC into a learning plan, not just a diagram. Keep a short assumptions log and review it monthly. If an assumption changes, update your activities or timeline.

Diagram

graph TB ToC["🎯 YOUR THEORY OF CHANGE

What conditions must be true
for it to work?"] Definition["📝 ASSUMPTIONS =
Conditions that must be true
for your ToC to work

If you don't name them,
you cannot test them.
That is a risk."] subgraph CommonAssumptions["📋 COMMON ASSUMPTIONS WORTH LISTING"] A1["Community will participate
if invited"] A2["Local leadership will
allow program access"] A3["Proposed activity fits
school or work calendar"] A4["Key staff will remain
in place during delivery"] end subgraph LinkBoxes["🔗 CAPTURE AT EACH LINK"] Link1["Activity → Output

What must be true?"] Link2["Output → Outcome

What must change
in behavior?"] Link3["Outcome → Impact

What must stay stable?"] end subgraph Types["🏷️ MARK ASSUMPTION TYPE"] Type1["🔍 TESTABLE NOW
Can validate in
the next month"] Type2["⏰ TESTABLE LATER
Requires time
or data"] Type3["🌍 OUTSIDE CONTROL
Needs a
mitigation plan"] end RiskRank["📊 RANK BY RISK

High risk + low evidence =
Test first

This turns your ToC into
a learning plan, not
just a diagram"] Log["📔 ASSUMPTIONS LOG

Review monthly
If assumption changes →
update activities or timeline"] TeamCheck["👥 TEAM CHECK-IN

Ask: 'Which assumption
worries you most?'

That is your first test"] ToC --> Definition Definition --> CommonAssumptions CommonAssumptions --> LinkBoxes Link1 --> Types Link2 --> Types Link3 --> Types Type1 --> RiskRank Type2 --> RiskRank Type3 --> RiskRank RiskRank --> Log Log --> TeamCheck style ToC fill:#F6F6F6,stroke:#737373,color:#2A2A2A style Definition fill:#FEF3C7,stroke:#F8CC1B,color:#2A2A2A style CommonAssumptions fill:#D9F99D,stroke:#72B043,color:#2A2A2A style A1 fill:#BBF7D0,stroke:#72B043,color:#2A2A2A style A2 fill:#BBF7D0,stroke:#72B043,color:#2A2A2A style A3 fill:#BBF7D0,stroke:#72B043,color:#2A2A2A style A4 fill:#BBF7D0,stroke:#72B043,color:#2A2A2A style LinkBoxes fill:#FED7AA,stroke:#F37324,color:#2A2A2A style Link1 fill:#FDBA74,stroke:#F37324,color:#2A2A2A style Link2 fill:#FDBA74,stroke:#F37324,color:#2A2A2A style Link3 fill:#FDBA74,stroke:#F37324,color:#2A2A2A style Types fill:#FEF3C7,stroke:#F8CC1B,color:#2A2A2A style Type1 fill:#D9F99D,stroke:#72B043,color:#2A2A2A style Type2 fill:#FEF3C7,stroke:#F8CC1B,color:#2A2A2A style Type3 fill:#FCA5A5,stroke:#E12729,color:#2A2A2A style RiskRank fill:#FEF3C7,stroke:#F8CC1B,color:#2A2A2A style Log fill:#FEF3C7,stroke:#F8CC1B,color:#2A2A2A style TeamCheck fill:#007F4E,stroke:#00b369,color:#fff,stroke-width:3px

Assumptions you should write down

Diagram