Definitions
Impact assessment, in plain terms
Five questions cover most of what people mean by impact assessment. The answers below match the visible FAQ at the bottom of the page; both are written for someone meeting the methodology for the first time.
What is impact assessment?
Impact assessment is a systematic process for measuring whether a program, policy, or investment changed outcomes for the people, communities, or environment it touched. It pairs quantitative indicators (numbers, scores, rates) with qualitative evidence (interviews, open-ended responses, narratives) and reports against a chosen framework such as IRIS+, the UN Sustainable Development Goals, GRI, or SASB.
The point of an assessment is to answer a specific question. Did the activity produce the change it set out to produce, and for whom. Said another way: was the program worth running, and is the next cycle worth running differently. An assessment that does not answer either question is data collection without a purpose.
What are the types of impact assessment?
Four working domains cover most assessments. Social impact assessment measures outcomes for people and communities. Environmental impact assessment studies effects on ecosystems and resources. Organizational assessment measures capacity and maturity inside an organization. Sustainability assessment tracks ESG performance over time. Adjacent forms include economic impact analysis, training and learning impact, gender-lens assessment, business impact analysis, and AI system impact assessment.
Most organizations need two or three of these, not all of them. A workforce nonprofit runs social and organizational. A renewable-energy fund runs environmental and sustainability. A multi-program foundation often runs all four across its portfolio. The common mistake is starting a new assessment from scratch each time. The four domains share the same architecture; the data does not need to.
What is an impact assessment framework?
An impact assessment framework is a structured language for what gets measured. The widely used ones are IRIS+ (from the Global Impact Investing Network, the de facto standard for impact-fund reporting), the UN Sustainable Development Goals (broad, often paired with IRIS+ for double-coding), GRI and SASB (sustainability and ESG reporting), B4SI (corporate community investment), and 2X Global (gender-lens).
The framework is only as useful as the evidence underneath it. Indicators retrofitted to an old dataset rarely fit. Frameworks chosen at scoping fit cleanly because the data dictionary already speaks the framework's language. Picking the prestige framework first and discovering you cannot collect its indicators is the most common scoping mistake in impact assessment.
What is the impact assessment process?
Five stages, in order. Scope: name the change you want to measure and the question the assessment has to answer. Baseline: capture starting conditions before the program acts on the participant or site, with a stable identifier so later records link back. Method: choose how the data will be collected, including whether you need a comparison group. Measure: run the instruments at the right cadence, usually pre, post, and follow-up. Report: produce a framework-aligned narrative that names what the data does and does not show.
The order matters more than any individual stage. Scoping after the survey is written produces an assessment that cannot answer the question. Skipping baseline produces an endline with nothing to compare against. Retrofitting a framework at report time produces alignment that does not survive a careful funder reviewer. Most assessment failures trace back to the order, not the technique.
What is the difference between impact assessment and impact evaluation?
Impact assessment measures what changed and reports against a framework. Impact evaluation asks whether the program caused the change, using a comparison group or counterfactual. Assessment can run on any program; evaluation requires the design choices that allow a causal claim. Many funders use the words interchangeably, and that is fine for everyday conversation. The design difference still matters when the question is "did our program produce this outcome, or would it have happened anyway."
In practice, assessments produce the running record of outcomes across cycles. Evaluations produce the periodic causal study that depends on baseline data, comparison conditions, and a sample size that supports inference. Programs that have done assessment well for several cycles can usually run a credible evaluation when a funder asks. Programs that have skipped baseline cannot.
Distinctions
Related-but-different terms
Assessment vs. Analysis
Impact assessment vs. impact analysis
Impact analysis is a technical term used in software engineering and business continuity to mean change-impact analysis. Outside those fields, "impact analysis" is sometimes used loosely to mean impact assessment. The two are not the same. Impact analysis tools and frameworks for SaaS are change-management software, not measurement software.
Assessment vs. Measurement
Impact assessment vs. impact measurement
Impact measurement is the broader practice: collecting evidence of change continuously. Impact assessment is the report against a framework that the measurement system produces, on a defined cadence. Measurement runs every day. Assessment runs every cycle. Both depend on the same connected evidence.
Assessment vs. Evaluation
Impact assessment vs. impact evaluation
Assessment reports what changed. Evaluation tests whether the program caused the change. Evaluation requires a comparison condition. Many programs run assessment for years and an evaluation periodically when a funder commissions one.
Social vs. Environmental
Social impact assessment vs. environmental impact assessment
Social and environmental assessments differ in what they measure (people vs. ecosystems) and in regulatory weight (environmental is often legally required, social is often funder-driven). They share the same architecture: persistent IDs, mixed-method evidence, framework alignment, and continuous comparison.