BigCat Research

What is social impact and how is it measured?

Short answer: Social impact is the change in people's lives that an activity actually causes, positive or negative, intended or not, after you subtract what would have happened anyway. Social impact is measured by agreeing who is affected, writing down how the activity is supposed to lead to change (a theory of change), choosing outcome indicators, collecting baseline and follow-up data, and then estimating how much of the change belongs to your work. Counting people trained or events held is not social impact measurement; those are outputs.

Disclosure: BigCat Research sells social impact analysis, SROI measurement and impact evaluation reports. This guide is written for buyers in Türkiye and elsewhere; factual claims are cited to sources we opened, and the example figures in the first table are illustrative.

What is social impact?

Definitions vary, but three widely used reference points agree on the core idea.

The International Association for Impact Assessment (IAIA) defines social impact assessment as analysing, monitoring and managing "the intended and unintended social consequences, both positive and negative" of planned interventions such as policies, programmes, plans and projects.¹ The same document suggests treating social impacts as changes to one or more of the following: people's way of life, their culture, their community, their political systems, their environment, their health and wellbeing, their personal and property rights, and their fears and aspirations.¹

The OECD Development Assistance Committee's evaluation criteria, which Belgium's Special Evaluation Office applies to development cooperation,² describe impact as the extent to which an intervention "has generated or is expected to generate significant positive or negative, intended or unintended, higher-level effects".² Effectiveness is a separate criterion: whether the intervention achieved its own objectives and results.²

Social Value International puts it in plainer words: an account of social value "is a story about the changes experienced by people".³

Two things follow from these definitions. First, social impact includes harm and side effects, not only the results you hoped for. Second, it is about change for people, not about the activity itself.

Output, outcome or impact: what is the difference?

The SROI guide warns readers to be careful not to confuse outputs with outcomes, and gives a simple example: if a training programme aims to get people into jobs, completing the training is an output and getting the job is an outcome.⁴ Impact is then the part of that outcome your programme can claim once you remove what would have happened anyway and what others contributed.⁴

The numbers in the example column are illustrative, not from a real project. The point is the logic: each level needs different evidence, and only the last one is social impact in the strict sense.

How is social impact measured, step by step?

Methods differ, but the main standards share a common sequence. The SROI guide sets out six stages: establishing scope and identifying stakeholders, mapping outcomes, evidencing outcomes and giving them a value, establishing impact, calculating the SROI, and reporting, using and embedding.⁴ Even if you never put a money value on anything, the first four stages describe how a credible social impact measurement works.

1. Set the scope and name the stakeholders

Decide which activities and which period you are measuring, and list who is affected: participants, their families, staff, volunteers, local institutions, sometimes people who did not take part. The first of the eight Principles of Social Value is to involve stakeholders in deciding what gets measured and how it is valued.³

2. Write the theory of change

A theory of change, or impact map, shows how inputs lead to outputs and outputs to outcomes.⁴ Write it with the people affected, not only in the office; the SROI guide warns that stakeholders may describe the effects differently from you, "perhaps even in surprising ways".⁴ The Principles of Social Value also ask you to look for negative and unintended effects at this point.³

3. Choose indicators and collect a baseline

For each outcome, pick an indicator you can observe or ask about: income, sales, school attendance, confidence, a wellbeing score. Collect it before the programme starts or as early as possible. Without a starting point you can describe the situation at the end, but you cannot show change.

4. Collect evidence of the outcomes

Surveys give you scale; interviews and focus groups tell you why a change happened and what people value. The Istanbul and Izmir study described below combined surveys and focus groups.⁵ If participants speak different languages, the instruments have to work in each of them. If you are still deciding what the programme should target, a needs assessment usually comes before this step.

5. Separate your contribution from everything else

This is where measurement becomes impact rather than monitoring. The SROI guide uses four adjustments:⁴

• Deadweight: how much of the outcome would have happened even if the activity had not taken place.
• Displacement: how much of the outcome simply moved a problem or benefit somewhere else.
• Attribution: how much of the outcome was caused by other organisations or people.
• Drop-off: how much an outcome that lasts more than a year fades over time.

The stronger route is a comparison group. The UK government's Magenta Book says impact evaluation asks "What difference has an intervention made?", and that experimental and quasi-experimental designs answer it by comparing with a group that acts as a proxy for what would have happened, known as the counterfactual.⁶ A perfect comparison is rarely possible, so the SROI guide says deadweight is estimated by reference to comparison groups or benchmarks and will always be an estimate; without a suitable comparator you may have to rely on a "best estimate".⁴ Whichever route you take, say which one it was.

6. Report, value if useful, and use the result

You can stop at a well-evidenced description of outcomes and contribution, or go further and put money values on outcomes to calculate an SROI ratio.⁴ The seventh Principle of Social Value asks for verification in proportion to the decisions the result supports, with independent assurance for external reporting or major investment.³ To see how deadweight and attribution move a ratio, try our SROI calculator; its figures are illustrative.

Which method fits which question?

"Social impact measurement" covers several methods. They overlap, but they answer different questions.

Impact Frontiers describes its five dimensions as What, Who, How Much, Contribution and Risk; Contribution asks whether the outcomes were likely better than what would otherwise have happened, and Risk is the likelihood that impact will be different from what was expected.⁷ Those five questions are a useful checklist even if you use another method.

If you are deciding between SROI and an economic appraisal, see SROI vs cost-benefit analysis. If you need to decide when to measure, see forecast vs evaluative SROI.

What does this look like in Türkiye?

Two published studies from Türkiye show the steps above in practice. BigCat Research prepared the My Sister report and carried out the survey and focus groups for the Istanbul and Izmir study; both reports are published by Habitat Association (Habitat Derneği).⁵⁸

Refugee and host-community women in Istanbul and Izmir. The project "Strengthening the Social and Economic Stability and Resilience of Syrian and Host Community Women and Girls in Turkey" was funded by the Government of Japan and implemented by UN Women with Habitat Association.⁵ The impact analysis first identified stakeholders, then built theories of change, then ran surveys and focus groups.⁵ The sample used maximum variation sampling, and surveys and focus groups were run in Turkish and Arabic so that all target groups could take part.⁵ The survey had 112 respondents and the focus groups 38 participants.⁵ The report calculated a social return of 2.57 TL for every 1 TL invested.⁵ Our project page summarises the study.

My Sister (Kız Kardeşim) Project. The 2021 social impact analysis designed questionnaires around the project's goals, surveyed participants selected by maximum variation sampling (566 responses), built theories of change for each training, and used the SROI method.⁸ It found that each 1 TL invested produced 2.44 TL of social return.⁸ See the project page.

Do not read 2.57 as "better" than 2.44. The SROI guide says that because organisations work with different stakeholders and make different judgements, it is not appropriate to compare social return ratios alone; an organisation should compare its own ratio over time.⁴

Common mistakes when measuring social impact

• Reporting outputs as impact. "1,000 people trained" is an output.⁴
• No baseline. You end up describing a situation, not a change.
• Ignoring negative effects. All three reference frameworks above include negative or unintended effects.¹²³
• Claiming all the change. Without deadweight and attribution, the result overclaims; "Do not overclaim" is one of the eight Principles of Social Value.³
• A single number with no method. A ratio or score without its assumptions cannot be checked.⁴

If you are about to commission a study, our guide to commissioning a social impact assessment or SROI lists what the brief should include. For a list of providers to compare, see social impact analysis companies. More method guides are in our guides.

FAQ

1. What is social impact in simple terms? Social impact is the change in people's lives that an activity causes, positive or negative, intended or unintended. IAIA describes social impacts as changes to areas such as people's way of life, community, health and wellbeing, and fears and aspirations.¹

2. What is the difference between social impact and outcomes? An outcome is a change that happened for people, such as getting a job after training. Social impact is the part of that change your activity caused, after removing what would have happened anyway and what others contributed.⁴

3. How is social impact measured if there is no control group? Collect a baseline, evidence the outcomes with surveys and interviews, then estimate deadweight, attribution and drop-off from stakeholder answers and external data, and state those estimates openly.⁴ A comparison group gives stronger evidence where it is feasible.⁶

4. Do we need SROI to measure social impact? No. Social Return on Investment (SROI) is one method that puts money values on outcomes.⁴ An impact evaluation or a social impact assessment can measure impact without monetising it.¹⁶

5. Can two SROI ratios from different projects be compared? Not on their own. The SROI guide says different stakeholders and judgements make comparing ratios alone inappropriate; compare your own ratio over time and read the assumptions behind any other figure.⁴

Sources

Author: BigCat Research team. Last reviewed: 15 October 2026.