Every time the issue changes the assignee, the Jira registers transition from the previous assignee to a new one.
Therefore, you might find the number of changes by looking up the number of transitions from the assignee in a predefined measure “Transitions from assignee”.
However, to count the number of assignees that have been assigned to the issue, you need to go through the Assignee dimension and filter the relevant ones.
The expression might be as follows.
--set of assignees
--condition for filter
[Measures].[Transitions from assignee]>0
The transitions-related measures are from the “heavy end” of calculations. Therefore, they are best performed on a limited set of issues if you have a Jira instance with many issues and multiple transitions within each issue.
If you only have one member of each dimension, you do not need the Aggregate function, and if there is only one condition, you do not need to put it in brackets.
You might as well use a zero instead of “false”.
Your expression might then look as follows.
([Measures].[Transitions to status issues count],
However, if you need further assistance, please get in touch with eazyBI support directly over e-mail since the behavior of that expression depends on the report context.