# What does "conservative" mean in the Integrity Council for the Voluntary Carbon Market (ICVCM) test for how carbon credits are quantified?

Canonical: https://senseible.earth/answers/ccp-conservative-likely-very-unlikely-meaning

The test has two parts: it must be likely that the quantified reductions are not overestimated, and very unlikely that they are very significantly overestimated. The framework reads likely as 66 to 100 percent probability and very unlikely as 0 to 10 percent, following the Intergovernmental Panel on Climate Change (IPCC).

## The two-part test

1. It is likely that the quantified emission reductions or removals using the methodology are not overestimated, taking into account the overall uncertainty.
2. It is very unlikely that reductions or removals using the methodology can be very significantly overestimated.

## What the probability words mean

Footnotes to criterion 10.1 say "likely" is used per the IPCC as sixty-six to one hundred percent probability, and "very unlikely" as zero to ten percent, and that where a multi-stakeholder working group assesses a category against the requirement, the assessment would be guided by the IPCC usage.

## Uncertainty has to include everything

The overall uncertainty includes assumptions such as the baseline scenario, estimation equations or models, parameters such as how representative default values are, and measurement approaches such as the accuracy of methods. It is assessed as the combined uncertainty from individual causes.

## One way to get there

A footnote names one possible means, among others: applying in the methodology a discount factor commensurate with the overall uncertainty of the quantified reductions.

## What it means for your own numbers

- Our reading: where you must choose between a measured value and a default, the more cautious choice protects the claim.
- Keep the meter calibration record and the source of every default you use.

## A discount in numbers

- Quantified reduction before any discount: 1,000 tonnes of carbon dioxide equivalent (CO2e)
- Discount for overall uncertainty: 10 percent, which is 100 tonnes
- Credited: 1,000 minus 100 = 900 tonnes of CO2e

The figures are our example of how a discount works. The framework gives no discount value and leaves the method to each methodology.

## What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, which gives a project its own fuel and power history. Credits are issued by the program's registry and checked by an independent verifier, not by Senseible's own check.

- [Uncertainty in a greenhouse gas inventory](https://senseible.earth/answers/ghg-inventory-uncertainty-calculation)
- [Over-crediting in cookstove projects](https://senseible.earth/answers/cookstove-carbon-credits-over-crediting)
- [Rice credits and the uncertainty deduction](https://senseible.earth/answers/rice-awd-credits-uncertainty-deduction-and-scale-limits)
- [Carbon credits for Indian businesses](https://senseible.earth/carbon-credits)

Sources: [Integrity Council for the Voluntary Carbon Market, Core Carbon Principles Assessment Framework, Section 4, January 2024, version 1.1 (criterion 10.1, footnotes 22 to 24)](https://icvcm.org/wp-content/uploads/2024/02/CCP-Section-4-V1.1-FINAL-15May24.pdf)

Last reviewed 2026-11-05. Based on Assessment Framework version 1.1 (January 2024). The Integrity Council's August 2026 rule architecture says Interpretations and Technical Notices may affect how criteria are assessed, so check icvcm.org for any in effect before you rely on a detail.