Reference

Social value glossary

Plain-language definitions of the terms you will encounter when writing social value bid responses for UK public sector tenders. Terms are listed alphabetically. Where a term has a dedicated guide, that is linked from the entry.

Attribution

An SROI adjustment that accounts for the share of a social outcome genuinely attributable to your organisation, as opposed to other contributing parties. If a training outcome is jointly delivered by your organisation and a subcontractor, attribution adjusts the claimed social value to reflect only the portion your organisation is responsible for. Applied as a percentage reduction to the gross proxy value.

Deadweight

An SROI adjustment representing the proportion of a social outcome that would have occurred anyway, without your organisation's involvement. For employment commitments, deadweight reflects the likelihood that the individuals hired would have found work within the same period regardless of your contract. Applied as a percentage reduction to the gross proxy value before other SROI adjustments.

Displacement

An SROI adjustment that captures any negative impact elsewhere caused by your social value activity. For example, if local employment commitments fill roles that would otherwise have been taken by other local candidates who remain unemployed, some of the social benefit is displaced rather than created. Displacement is typically smaller than deadweight or attribution adjustments for the commitment types common in public procurement.

HACT Social Value Bank

A published dataset of proxy values for social outcomes related to housing, wellbeing, and community development, produced by HACT (the Housing Associations' Charitable Trust). HACT proxy values are used as a supplementary source alongside National TOMs, particularly for employment, disability, and wellbeing-related commitments.

HM Treasury Green Book

The UK government's guidance for the appraisal and evaluation of public spending. The Green Book publishes unit costs for a range of social outcomes, including the social cost of carbon (used to value CO₂ emissions avoided). Green Book figures are recognised reference values for public sector appraisal and are used in social value calculations where TOMs proxy values are not available.

ITT (Invitation to Tender)

The formal document issued by a buyer to invite suppliers to submit a bid for a public contract. The ITT typically includes the specification of requirements, evaluation criteria, weighting, and submission instructions. The social value section of the ITT describes the framework the buyer is using, the weight assigned to social value in the overall evaluation, and any specific themes or commitments the buyer has prioritised.

Model Award Criteria (MAC)

The Cabinet Office's standardised evaluation criteria for social value under PPN 06/20. The MAC provide a common basis for central government buyers to assess supplier commitments across the five PPN 06/20 themes. Evaluators using the MAC score responses on a numerical scale against criteria aligned to each theme. See the PPN 06/20 guide for detail.

National TOMs

National Themes, Outcomes and Measures — a social value measurement framework developed by the Social Value Portal and widely adopted by UK local authorities, housing associations, and NHS trusts. The framework provides a standardised taxonomy of outcomes (Jobs, Growth, Social, Environment, Innovation) with published monetary proxy values for each. See the National TOMs guide for detail. See the National TOMs guide for detail.

PPN 06/20

Procurement Policy Note 06/20 — the Cabinet Office policy requiring central government contracting authorities to evaluate social value explicitly in qualifying procurements, with a minimum weighting of 10% of the total evaluation score. PPN 06/20 establishes five themes (COVID-19 recovery, tackling economic inequality, fighting climate change, equal opportunity, and wellbeing) and associated Model Award Criteria. See the PPN 06/20 guide for detail. See the PPN 06/20 guide for detail.

Proxy value

A monetary figure that represents the social benefit of one unit of a specific outcome. Proxy values allow qualitative social outcomes — an apprenticeship, a training day, a local employment hire — to be expressed in a common financial unit so they can be compared, totalled, and evaluated. Published proxy values come from recognised datasets such as National TOMs, the HACT Social Value Bank, and HM Treasury Green Book figures.

Social Return on Investment (SROI)

A methodology for calculating the net social value generated per pound of investment, after applying three adjustments — deadweight, attribution, and displacement — to a gross proxy value figure. SROI produces a ratio (e.g. £4:£1) that expresses how much net social value is created for each pound spent. Required in procurement when the ITT explicitly specifies SROI methodology. See the SROI vs TOMs guide for when and how to apply it. See the SROI vs TOMs guide for detail.

Social Value Act 2012

The Public Services (Social Value) Act 2012, which requires public authorities in England and Wales to consider the social, economic, and environmental wellbeing implications of their procurement decisions before contracting for services. The Act was the legislative foundation for subsequent policy developments including PPN 06/20, which strengthened the requirement from 'consider' to 'explicitly evaluate' for central government.

Social Value Portal

A technology platform commercially associated with the National TOMs framework. Social Value Portal software is used primarily by buyers — local authorities, housing associations, NHS trusts — to track and report supplier social value delivery post-award. It is a buyer-side reporting tool, not a supplier-side bid writing tool. For the distinction and supplier alternatives, see the alternatives to Social Value Portal page. See the alternatives to Social Value Portal for detail.

TOMs (Themes, Outcomes and Measures)

The structural unit of the National TOMs framework. Each TOM identifies a specific social outcome (for example, TOM 1a: Creating Employment for Local People), a measurement unit (per person employed), and a published proxy value (£12,654). When a supplier commits to a number of units against a specific TOM, the proxy value is applied to calculate the claimed social value for that commitment.

Weighting

The percentage of the total evaluation score allocated to social value in a procurement. Under PPN 06/20, social value must be weighted at a minimum of 10%. Local authority and NHS buyers may weight social value at 10–20% or higher, depending on contract type and their stated priorities. The weighting determines how much competitive advantage a strong social value response can deliver, and therefore how much bid writing effort is warranted.