Logic model
A one-page diagram linking a program's inputs and activities to its outputs, outcomes, and impact.
What it means
A logic model is a visual chain — inputs (resources), activities (what is done), outputs (direct products like sessions delivered), outcomes (short- and medium-term changes), and impact (long-term effects) — used to plan, communicate, and evaluate an intervention. It clarifies the difference between activity and effect: counting workshops held (output) is not the same as skills gained (outcome). Compared with a theory of change, it is typically more linear and operational, emphasizing the what and the measurable rather than the why and the assumptions; the two are often used together. Its weakness is that the neat left-to-right flow can imply a certainty and simplicity that complex social problems rarely have. It matters as the workhorse template for grant proposals and monitoring frameworks, forcing teams to distinguish effort from results.
Examples
A job-training logic model lists funding and trainers (inputs), courses run (activities), participants certified (outputs), employment gained (outcome), and reduced poverty (impact).
A food bank's logic model separates vans and volunteers (inputs) from parcels delivered (output) and the actual aim: fewer households skipping meals (outcome). Counting parcels is not proof of that.
A hospital's hand-hygiene programme charts dispensers and training hours as inputs, staff sessions run as output, and lower infection rates as the outcome — so nobody mistakes attendance for cleaner wards.
First described in Program-evaluation practice (1970s–90s).