Prioritize Work Items on a custom field

By default, the prioritization feature uses the standard Priority field of Work Items (field ID priority), writing a value to that field. However, it is not necessary to prioritize items on that field. You can prioritize items on any existing custom field, subject to the following limitations:

The custom field must be of the same type as the default Priority field, i.e. float.
The custom field must be configured for all the types of Work Items listed in the prioritization table.
For example, suppose the table contains both Requirements and Test Cases, and that Test Cases have been configured with a custom field "Test Priority", of float type. This field will not be available to select as the prioritization field because the Requirement type items do not have it. The table would have to contain only Test Cases in order to prioritize them on the custom field. This is easily done by build and run a query that retrieves only Test Cases.

Open the Prioritization pane as described earlier.
Run a query that retrieves only Work Items having the desired custom field.
Optionally select a subset of the items in the table.
In the Prioritization sidebar, click and select Change Prioritization Field on the menu.
In the Change Prioritization Field dialog, select the field on which to prioritize the items.

Note:

The dialog lists only those fields valid for all the items and that the standard Priority field is always present in the list.