I don't think this is advisable for many reasons, one being that maintaining the workflow stated becomes tied to your customization. This should be provided and stored in the data warehouse if at all possible.
Another approach is https://github.com/jazz-community/rtc-statushistory-presentation which gets the information out of the history. You could also run some automated tool that calculates the information (e.g. nightly) and stores it in another database.

Finally:

There is no good way to implement something like this using the JavaScript attribute customization API, because detecting the state change is so hard. You could use a follow up action on work item save. This has still issues because the artificial second save can collide with the user UI activities. You have been warned.


Here examples how to update work items in the server API

https://rsjazz.wordpress.com/2012/11/27/resolve-parent-if-all-children-are-resolved-participant/
https://rsjazz.wordpress.com/2012/07/31/rtc-update-parent-duration-estimation-and-effort-participant/

Hi Varun,

Have you investigated the reporting options in JRS?  You may wish to review : https://jazz.net/library/article/1540

Introducing Historical Trend Reporting in Jazz Reporting Service Report Builder 6.0.1

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Appendix

Change and Configuration Trend Details