> For the complete documentation index, see [llms.txt](https://docs.enlyze.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.enlyze.com/en/production-optimization/downtimes/defining-reasons.md).

# Build the downtime catalog

All configured downtime reasons together form the **downtime catalog**. When [assigning reasons](/en/production-optimization/downtimes/assigning-reasons.md), employees always pick a reason from this catalog. A well-built catalog is therefore the foundation of every downtime analysis.

{% hint style="info" %}
What the three downtime categories (Planned, Unplanned, No Production Planned) mean and why assignment matters is explained under [Categories & assignment (Concepts)](/en/concepts/downtimes/categories-and-assignment.md).
{% endhint %}

## Why completeness matters

New reasons cannot be created while assigning. In addition, users with the **Operator** role cannot edit the catalog (see [Roles & permissions](/en/administration/user-management.md#roles-and-permissions)). If a reason is missing from the catalog, there are only two ways out: the downtime gets an inaccurate reason, or none at all. Both distort the analysis, for example the Pareto analysis of the most frequent downtime causes.

Build the catalog as complete as possible. It does not have to be perfect from day one: what matters is that it covers the most frequent causes and is then [evolved continuously](#evolve-the-catalog).

## Prerequisites

Before building the catalog, [downtime detection](/en/production-optimization/downtimes/detection.md) must be configured for the relevant machine.

## Configure reasons

{% stepper %}
{% step %}

#### Open downtime reasons

Navigate to **Settings > Reasons for downtime**.
{% endstep %}

{% step %}

#### Add reasons

Add downtime reasons under the appropriate category (**Planned**, **Unplanned**, **No Production Planned**). Optionally, organize reasons into groups for better manageability.

<figure><img src="/files/GoCESemwKll3Bi1tEkqu" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}

#### Save

Click **Save** to apply your changes.
{% endstep %}
{% endstepper %}

## Design a good catalog

These guidelines have proven useful when building a downtime catalog:

* **Start with the most frequent causes.** Go through the downtimes of the past weeks and collect the causes that keep recurring. A catalog that covers the most frequent cases beats a theoretically complete one that never gets finished.
* **Develop the catalog together with the shopfloor.** The people who will assign reasons later know the typical faults best. Use their wording so the right reason is found quickly during assignment.
* **Choose a manageable granularity.** A reason should be specific enough to derive an action from it ("film tear" instead of "malfunction"), but not so fine-grained that picking one becomes a search task.
* **Use groups for structure.** Groups (for example by machine section or fault type) keep even a large catalog easy to navigate.
* **Use catch-all reasons sparingly.** A reason like "Other" is worthless for analysis. If it is picked frequently, concrete reasons are missing from the catalog.

## Evolve the catalog

A downtime catalog is never truly finished: new products, retrofits, or previously unknown fault patterns bring new causes with them. Review the catalog regularly, for example as part of your downtime analysis.

Typical signals that reasons are missing from the catalog:

* Employees describe the actual cause in a downtime's **comment** because no fitting reason exists.
* Catch-all reasons like "Other" are picked noticeably often.
* Many downtimes remain without an assigned reason.

You can add new reasons at any time under **Settings > Reasons for downtime**. Already assigned reasons are not affected by this.

## Related topics

* [Assign reasons to downtimes](/en/production-optimization/downtimes/assigning-reasons.md): Assign reasons from the catalog to detected downtimes.
* [Categories & assignment](/en/concepts/downtimes/categories-and-assignment.md): Background on the three downtime categories and the catalog.