> ## Documentation Index
> Fetch the complete documentation index at: https://docs.isometric.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Key Certify Concepts

> Key concepts used in Certify and the Certify API including sources, datapoints, components, GHG entries, and feedstock types

This page defines concepts used in Certify, and the [Certify API](/api-reference/certify/certify-introduction), which are helpful to understand when submitting information for verification via Certify. For a broader understanding of Isometric's verification processes on the Isometric Registry, please refer to the [Isometric Standard](https://isometric.com/standard).

## Resource visibility

* Until resources are submitted as part of a GHG statement, they are visible only to members of your organization.
* After statement submission, they are visible to the verifier assigned to the GHG statement.
* Once credits have been issued, GHG entries are added to the [public registry](https://registry.isometric.com), and associated resources are visible publicly, with the exception of source documents.
* Sources uploaded in the Certify platform are kept private by default once published on the Isometric registry (file names will be displayed). Contact Isometric to update public source visibility. Sources [added via the API](/api-reference/certify/post-source) can be set `public` on submission.

## Resources

The main resources used in Certify are sources, datapoints, components and GHG entries.

### Sources

* Sources represent a piece of evidence for a particular datapoint used in carbon accounting calculations.
* Source documents are private, and only shared with the verifier assigned to a related GHG entry.
* Other information associated with a source, such as its display name, is visible publicly once the GHG entry is on the public registry.
* Verifiers are not notified when new sources are added to datapoints in a submitted GHG entry, but they will immediately have access to the source documentation. Please notify the Isometric Registry Operations team when sources are added on a verifier's request so that we can ensure that the verifier is aware.

### Datapoints

* Datapoints represent any value used in carbon accounting calculations.
* When creating datapoints, sources should be referenced to provide evidence for the value used.
* A standard deviation should be provided if the datapoint is to be included in the variance propagation method of uncertainty analysis.
* All datapoints are considered statistically independent for the purpose of variance propagation, although if a datapoint is used twice within a GHG entry calculation, this dependence is captured.

### Components

* Components represent physical activities whose CO₂e flux needs to be accounted for.
* Components are created from [component blueprints](/user-guides/certify/component-blueprint-library) that contain sets of equations used to calculate a transfer of CO₂e into or out of the atmosphere.
* A blueprint defines a set of inputs that are the datapoints to be used in the calculation. For instance, a transport emissions blueprints would ask for datapoints representing a distance, mass and carbon intensity.
* When creating a component from a blueprint, the blueprint must be specified, as well as a list of datapoints for the expected blueprint inputs. Learn more about components in [Identifying Components](/user-guides/certify/identifying-components).

### GHG entries

* GHG entries represent a series of activities that result in CO₂e being removed from the atmosphere or reduced relative to a baseline.
* The carbon accounting of a GHG entry typically contains sequestrations, counterfactuals and activities (emissions).
* GHG entries are structured using a template, [defined in your LCA](/user-guides/certify/lca).
* Templates are divided into component groups. For instance, a biochar template may contain a `Feedstock sourcing` group.
* Groups can contain multiple components.
* Components can also be partially attributed to GHG entries, if the activity the component represents contributed to multiple GHG entries.
* The final uncertainty discounting is done on the GHG entry level - the API will return the CO₂e removed with and without discounting.
* See the [Create a GHG entry](/user-guides/certify/ghg-entry) guide for more details.

### Feedstock types

* Many carbon removal methods involve a feedstock, for instance biomass feedstock in BiCRS or silicate rock in enhanced weathering.
* Feedstock types are used to describe the feedstock used in a GHG entry.
* When creating a GHG entry, a feedstock type can be optionally specified so that Isometric and verifiers can see which GHG entries use which feedstocks.
* This is important if different feedstocks are used in a single GHG statement.
* See the [Add feedstock](/user-guides/certify/add-feedstock) guide for more details.