A logic model is the one-page schematic of a programme’s results logic: inputs (resources) feed activities, which produce outputs (the countable products of activity), which are expected to yield outcomes (changes in participants or systems) and, eventually, impact. Its virtues are exactly its constraints — brevity, a shared vocabulary, and a format funders and boards read fluently. Its vice is seduction: the columns look like causation while asserting only sequence, and a programme can have an immaculate logic model and no defensible reason to believe column three causes column four. Used knowingly — as a summary of a theory, not a substitute for one — it remains the most efficient planning and evaluation scaffold in the field.
The columns, and the line that matters most
Inputs: funding, staff, partners, facilities — what the programme consumes. Activities: what it does with them. Outputs: direct, countable products — sessions run, people trained, materials distributed. Outcomes: changes in knowledge, behaviour, condition — usually split short/medium/long term. Impact: the population- or system-level change the programme exists for.
The most consequential line in the model is the output–outcome boundary. Everything left of it is under the programme’s control and will happen if the team shows up; everything right of it happens in other people’s lives and might not. Evaluations that report outputs as achievements are trading on the reader not noticing the line.
Good models also carry two margins the template often omits: external factors (what else moves the outcomes) and assumptions (why anyone believes the arrows) — the minimal imports from theory-of-change practice that keep the page honest.
Canonical sources
The programme-evaluation formulation is anchored by McLaughlin and Jordan’s Logic models: a tool for telling your program’s performance story00042-1), which frames the model as the backbone for performance measurement and evaluation design.
The most widely used practitioner guide is the W.K. Kellogg Foundation’s Logic Model Development Guide (W.K. Kellogg Foundation), the source of the standard five-column template and the workshop practices most organisations imitate.
The format’s family resemblance to results chains and logframes is real: the logic model is the diagrammatic summary; the logframe is its management-matrix cousin with indicators and risks attached.
What the format is good for
- Design triage: a draft model exposes programmes that are all activity and no outcome pathway in about an hour.
- Shared reference: boards, funders, implementers, and evaluators pointing at the same page — the coordination value is easy to underrate.
- Evaluation scaffolding: indicators mapped to columns, evaluation questions to arrows; the model is the cheapest way to make an M&E plan coherent.
- Not causal argument: the arrows summarise beliefs argued elsewhere (or not at all). Complex, adaptive, or contested programmes need a theory of change behind the page.
- Not a straitjacket: programmes that iterate weekly need living models; a laminated logic model governing an adaptive programme is managing last year.
Building and using one
Draft outcomes first, then work left
Write the outcome and impact columns before activities — the reverse of how teams naturally think and the single practice that most improves models, because it forces activities to justify themselves against changes.
Keep outputs honest and countable
Outputs are verifiable products (“12 workshops, 240 completers”), not weak outcomes (“increased awareness”). If it happens inside participants, it is an outcome and belongs right of the line.
Specify outcomes as who-changes-what-by-when
“Improved wellbeing” plans nothing. “Participating caregivers report reduced parenting stress at six months” is measurable, attributable to a timeframe, and assignable to an indicator.
Attach indicators and evidence sources per column
Each output and outcome gets its measure, source, and collection moment. This is where the model becomes an evaluation plan instead of a poster.
Version it against reality
Review at implementation milestones: which arrows are holding, which outputs are not converting, what external factors turned out to matter. A dated version history converts the model from proposal art into management instrument.
Worked example: a food-bank’s model finds its missing column
A food-bank network drafted a logic model for its new “more than food” strategy. The first draft was symptomatic: activities (parcels, advice sessions, referrals) flowed to an impact of “reduced food insecurity”, with the outcome column filled by restated outputs — “clients receive advice” standing where a change should be.
Outcomes-first redrafting forced the real question: what change in whose situation? The revised column read “clients resolve the benefit or debt issue driving food-bank use (3 months)” and “repeat-visit rate falls among advised clients (12 months)” — outcomes the network had never measured. Indicators were attached (case resolution from advice-partner records; visit patterns from its own database), and “external factors” recorded what everyone knew and the old model hid: local benefit-processing delays moved demand more than anything the network did.
Twelve months later the versioned model told a useful story: advice uptake converted poorly from parcels alone (output→outcome arrow weak), tripling where advisers sat in the distribution centre (a delivery change the review triggered), while repeat-visit reduction tracked the external benefits backlog — reported as context, not claimed as impact. The one-pager had done its job: not proving causation, but making the programme’s claims, measures, and surprises legible on a single sheet.
Common mistakes
- Outputs dressed as outcomes. “500 people trained” in the outcome column is the format’s signature abuse.
- Arrows as evidence. Reading the diagram’s left-to-right flow as demonstrated causation, then reporting accordingly.
- The immaculate model. No external factors, no assumptions — a programme operating in vacuum, on paper only.
- Everything models. Ten activities, thirty outcomes, all connected: a model that cannot discipline anything.
- One-and-done. Built for the funding bid, never revisited; the review-and-version step is what separates instrument from ornament.
- Impact claimed at output speed. Long-term impact rows reported in year one from short-term proxies, with the timeframe quietly dropped.
Limitations
The format is linear and tidy; programmes are neither. Feedback loops, participant agency, and adaptive change fit the page badly, and complex interventions summarised into five columns lose exactly the dynamics that determine their success.
The model asserts sequence, not mechanism — why the arrows should hold is outside the format. Paired with a theory of change it summarises well; alone it can launder assumption into apparent plan.
And its legibility to funders creates its own incentive: models optimised to look fundable rather than to be true. The discipline against that is versioning against evidence, which no template supplies — only management practice does.
Where software helps
The model’s outcome columns run on evidence that is often qualitative — participant interviews, advice-session notes, partner reports — and connecting that material to specific outcomes is codebook work: Evidano codes it against the model’s outcome and assumption set, with quotes linked, so quarterly reviews read evidence per arrow instead of anecdotes per meeting. Open-ended feedback at output points (session forms, referral notes) aggregates the same way.
The modelling itself is a team’s thinking made compact; no tool should generate it, and a generated one would encode nobody’s actual commitments — which is the only thing a logic model has to offer.
Topics
- logic model
- logic model evaluation
- inputs outputs outcomes
- programme logic
- results framework
- outcome measurement
Other methods in theory-based and logic approaches
Written guides are linked directly; the rest have a reference entry in the methodology directory.
Keep reading
- Research MethodsLogical Framework Approach: the logframe, used properlyThe 4×4 logframe matrix: vertical logic, indicators, means of verification, and assumptions — how to build one, and how to stop it fossilising an adaptive programme.
- Research MethodsTheory of Change: mapping how a programme is supposed to workHow to build and use a theory of change: outcomes pathways, assumptions made testable, and evaluation designed against the theory — plus the ritual-diagram failure mode.
- Research MethodsSocial Listening: qualitative analysis of public digital talkBeyond dashboards: designing queries, cleaning and sampling social data, reading conversations in context, and the representativeness caveats that keep findings honest.
