> For the complete documentation index, see [llms.txt](https://kb.bravegen.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kb.bravegen.com/carbon/core-concepts/activity-sources/metric-sources.md).

# Metric Sources

Collect non-emissions metrics and control their emissions calculation and reporting treatment.

In some cases your organisation may want to collect and report on non-emission related values, eg. Full Time Employees (FTE), or Net Lettable Area (NLA). These values can be ingested via the normal [data collection](/carbon/core-concepts/data-collection.md) process. Bravegen considers all Activity Sources to be 'metric' sources.

### Excluding from Emissions Calculation

When sources arrive at the [task review](/carbon/core-concepts/data-collection/tasks/task-reviews.md) step, you have the opportunity to assign an [inventory rule](/carbon/core-concepts/inventory-items/inventory-rules.md) to them. If you wish to include the data in a framework report **without** calculating emissions, you can assign or create an inventory template with the GHG category: 'Other'. Inventory items in this category are included as separate line items from regular GHG Scope 1,2,3 reporting totals. Do **not** assign an emission factor to this template if you do not want to calculate emissions.

### Excluding from Reporting

If you want to use the collected data for calculation or BI purposes only, then you should set the inventory rule to 'none'.

### Aggregation Methodology

All sources have an *aggregation* property. This defines how data in the source is reported if there are multiple data entries during the reporting period. A source can only have a single aggregation method - this is updated from the source details view.

<table><thead><tr><th width="141.91015625">Methodology</th><th>Behaviour</th><th>Examples</th></tr></thead><tbody><tr><td>SUM</td><td>Data entries are summed across the reporting period. (Default)</td><td>Eg. Spend or volume, where totals are used</td></tr><tr><td>LATEST</td><td>The latest entry value is used from the reporting (or previous) period.</td><td>Eg. Ratings, FTE, Floor Area</td></tr></tbody></table>

{% hint style="info" %}
Note: BraveGen will apply the Aggregation Methodology when rolling up data across entities.&#x20;
{% endhint %}

Monthly is our lowest reporting granularity, so Source Data is kept at monthly grain. Transactional records within a month are grouped into a single monthly row. This grouping has nothing to do with the Aggregation Method, it is a fixed data reduction rule.&#x20;

As a result a source with LATEST method holds at most one value per month. If a new value arrives for a month that already has one, it replaces the old value, it is never added to it.

Original CSV files are kept unchanged, with their checksums, as the audit record. Any monthly row can be rebuilt from the transposed files if it is ever questioned.

#### FAQs

<details>

<summary>Is it possible to have different aggregation methods on a single source?</summary>

No this is defined once per source, and carries across all activity for the source.

</details>

<details>

<summary>Will changing aggregation method have an impact on my historical reporting?</summary>

Yes! All historical data for the source will be recalculated to match, which may trigger a base year recalculation! It is not recommended to change the aggregation value, unless correcting an incorrectly set value.

</details>

<details>

<summary>If I have multiple values loaded against a single month, how is this resolved for a source with LATEST aggregation?</summary>

Only the most recent value for that month is reported / used in reporting

</details>

<details>

<summary>Does the aggregation method also apply to a <a href="/carbon/core-concepts/data-collection/manual-adjustments.md">manual data entry</a>?</summary>

Yes, this is resolved based on the date assigned to the activity in the manual data entry.

</details>