Need duration of tasks from creation time to first assignment to a user as a report

[Mahesh Kumar2]

I want to capture the duration of a task on RITM from creation time to first assigned to some user via metrics or something. Please help on the same

[suvro]

Explore metrics you will find a way to do that. OR else create a duration type field in RITM table.

Write a Business Rule, when assigned_to changes and the duration type field you created is null.

then use the below community thread for setting the duration

https://community.servicenow.com/community?id=community_question&sys_id=0da20f21dbd8dbc01dcaf3231f961917

[Mahesh Kumar2]

Hi suvro, i need it on task, not on RITM

[Mahesh Kumar2 · Accepted solution]

Achieved it through metrics by calculating the time difference.

[Elizabeth10]

I need exactly the same - can you explain which metrics you have created and how you got it to work? 
Thanks.