Ask most teams for their Theory of Change and they'll open a slide which contains inputs, activities, outputs, outcomes and then impact. Five boxes and four arrows, built in an afternoon to satisfy a funder's template. It looks complete but it rarely is.

The diagram is not the Theory of Change. It's the record of one, made after the real work is already done or, more often, skipped entirely. The actual theory is the argument underneath: why do you believe this activity, with this group, in this context, leads to this change. That argument has assumptions buried in every arrow and most diagrams never make them visible. They show what connects to what. They don't show why anyone believes the connection holds.

This matters because the boxes are the easy part. Anyone can write "training delivered" leading to "skills improved." The harder, more useful work is interrogating that link before you draw it. Does this group need training, or do they already have the skill and lack the means to use it? Is the barrier knowledge, or is it access, or is it something the programme has no power to change at all? A diagram answers none of that. A conversation does.

This is why building a Theory of Change with a room full of people, especially the ones delivering the work and the ones receiving it, produces something fundamentally different from building it alone at a desk. The people closest to the problem are usually the first to spot where an arrow doesn't hold. That's not a weakness in the process but the process working.

Done this way, the diagram comes last as a summary of an argument that's already been tested and not a placeholder for one that hasn't.

A theory you can't defend in a room full of the people it's about, isn't a theory. It's a guess with good formatting.