Build a Report against "at cause" Assignment Group who broke SLA

[RC2]

There used to be a forum for Reporting only, but I can't find it now!! Hoping you can all help me.

In the ServiceNow Reporting Module, I need to build out a report that lists the Assignment Group that an Incident was assigned to when the "Made SLA" flag went from TRUE to FALSE. 

My guess is that it's on the "incident_Metric" table, but not sure what to query beyond that. 

To add to that, I need to add a layer where it only spits out the tickets that were "at one point" assigned to a list of Assignment Groups that I would define. 

Thoughts on how this could be achieved? I need this data urgently! The idea is that I need to calculate the percentage of tickets where the SLA was broken by "someone else" and not one of the listed Assignment groups. 

I would have to do Definition = Assignment Group, and Value would be assignment group names. But not sure how do the Made SLA part. 

[-O-]

The idea is that I need to calculate the percentage of tickets where the SLA was broken by "someone else" and not one of the listed Assignment groups.

That is not how it should be viewed.

SLAs can be broken by a single group: the accountable group - that usually is the Service Desk.

No matter what process is one considering, the accountable can only be one entity.

What you should do is to define OLAs for supporting/responsible groups and report on that.

Otherwise you will always find the situation that people re-assign their tickets 1 minute before the "Made SLA" switch, all the process becoming a "throw the responsibility to some other group" type of blame-someone-else-game.

If each group has an OLA, it will be easy to see which group spends the most time doing nothing.

It will no longer be possible to hide that a ticket stood assigned and not worked for weeks, just to re-assign it in the last minute, hiding the inaction under the rug.

[RC2]

I think that's already what I'm asking. The Task SLA tab in an incident can take me to a table with "percentages" and it shows which assignment group spent the most time on the ticket. I'm trying to build a report against that data, but can't seem to get it to work. I don't see a Metric table for the data, so all I can get is the current assignment group and currently SLA percentage. But if I look at the breakdown in order of the "life" of the ticket, I can see Team A did XXX, Team B did XXX, and Team C did XXX breakdown. I need to report against that list of tickets our teams worked on and then a separate Column that shows which team had the highest SLA on the ticket. It's more to gage whether our teams are sitting on tickets or whether other teams are (so we can improve processes).