IRIS+ is the generally accepted impact accounting system that leading impact investors use to measure, manage, and optimize their impact. Proper use of the IRIS+ system ensures a minimum level of consistency in a users’ impact claims and performance, which makes it easier for investors to analyze and extract useful information for decision making. Use of IRIS+ also facilitates the comparison of impact information.

The standards that underpin the IRIS+ system are updated on an ongoing basis in accordance with market evolution.

Updates to the system occur in a variety of ways:

  • Additions to the Core Metrics Sets are informed by the Navigating Impact project which draws from evidence-based research and a broad stakeholder consultation process, including open public comment periods.
  • New foundational materials, core concepts, additions to the IRIS Catalog of Metrics, and other implementation guidance are prioritized as a result of 3 inputs: ongoing and open call for market feedback, the biennial GIIN impact measurement and management survey, and internal agenda setting processes - all of which are subject to review by an Advisory Committee and coordination with other aligned standards bodies.

All new materials are added only after they have been vetted through stakeholder consultation typically in the form of an expert working group and then reviewed during a public comment period. Additional information about the IRIS+ standards development process is available here.

Core Characteristics of Impact Investing

Defines the baseline expectations for the practice of impact investing; provides investors clear reference points and practical actions they can take to scale their practice with integrity, including expectations for integrating impact information into investment management.

Fundamentals & Core Concepts

IRIS+ Fundamentals are foundational materials that set out the core concepts and objectives that guide the GIIN in its approach to setting standards for impact measurement and management.

Catalog of Metrics

Individual IRIS metrics are numerical measures used in calculations or qualitative values to account for the social, environmental and financial performance of an investment. The full catalog is offered in both a searchable and downloadable format to enable search and discovery of individual metrics. The GIIN offers the IRIS Catalog of Metrics as a public good.

IRIS metrics should be used and analyzed in combination according to the five dimensions of impact as well as other contextualizing factors to produce relevant and comparable impact performance information. Set up a free IRIS+ profile to set your preferences and acquire generally accepted IRIS+ Core Metrics Sets by theme or Sustainable Development Goal (SDG).

Aligned Standards

When formulating Core Metrics Sets and guidance for impact themes or by SDG, the GIIN considers the existing body of standards, evidence, and best practices. The GIIN partners to align standards whenever possible. The IRIS+ system references standard metrics and practices already in use by impact investors, from more than 50 entities.


The IRIS+ system is designed to minimize confusion for how to set objectives, describe and understand impact, assess success, and clearly communicate impact performance with other impact investing stakeholders. Using shared terms, definitions, and agreeing on core concepts is critical for a shared understanding and use of impact data in decision-making. The IRIS+ glossary defines technical terms and core concepts used throughout the system.

If you have an IMM term or core concept that should be included in this glossary and would like to submit it for inclusion, please fill out this form and we will get back to you shortly.