---
sourceDocument: Zurich IT Operations Management
sourceDocumentLink: https://www.servicenow.com/docs/r/zurich/it-operations-management

 Release :

    - zurich

ft:locale :

    - en-US

ft:publication_title :

    - Zurich IT Operations Management

ft:clusterId :

    - itom

bundleId :

    - itom

workflow :

    - Technology


---

# Add CMDB tables or classes for impact calculation

# Add CMDB tables or classes for impact calculation {#ariaid-title1}

* Release version: Zurich
* 
* Updated August 11, 2026
* 
* ![](https://www.servicenow.com/docs/portal-asset/ico-clock) 1 minute to read

Add the CMDB tables that contain application services to be considered during impact calculation, helping ensure accurate and relevant impact results.

## Before you begin

Role required: evt_mgmt_admin, evt_mgmt_operator, or evt_mgmt_user

## About this task

Organizations may have a vast number of CMDB tables---or classes---such as cmdb_ci_service_by_tags, cmdb_ci_service_auto and many others. However, not all of these are required for impact calculation. To streamline analysis and
avoid processing irrelevant data, you can selectively add or remove only those CMDB classes that represent critical infrastructure or components. The procedure below shows how to add a CMDB class. If you want to remove any CMDB table from the list, see [Remove CMDB tables or classes from impact calculation](https://www.servicenow.com/docs/~aygPg6vjSveV0hLot8DRA "Exclude unnecessary CMDB tables or classes from impact calculation to improve performance and focus on relevant data.").

When you add a CMDB class, all application services related to that class are considered for impact calculation. However, if you do not want to include all services of a specific class and only want
to select specific ones, you can do so on the Impact Filter Services page. For more information on how to include or exclude a service, see [Add application services for impact calculation](https://www.servicenow.com/docs/B9zDAon3yTie7J2QlZQNtw "Specify the application services that must be considered during impact calculation to ensure accurate service impact assessment.").

## Procedure

1. Navigate to All and search for <kbd class="ph userinput">em_impact_inclusion_class.list</kbd>.  
   The Impact Inclusion Classes page opens, displaying a list of CMDB classes that are included in impact calculation.  
2. Select New.  
3. From the Table field, select a CMDB table.  
   Note:  
   The list contains only the CMDB tables supported for impact calculation, not all CMDB tables.  

4. Select Submit.  
   The CMDB table adds to the list of impact inclusion classes.  
{#add-cmdb-tables-impact-cal__steps_k1m_yp4_lfc}