Resolved Alerts in Operations Manager is easy to extract from your DW and Operations Manager environment:

In Powershell:

Get-Alert | Where {$_.Resolutionstate -eq 255} | ft resolvedby

Or if you need a query from OperationsManagerDW in SQL as a dataset in your report:

SELECT Alert.vAlert.AlertName, Alert.vAlertResolutionState.ResolutionState, Alert.vAlertDetail.Owner, Alert.vAlertDetail.TicketId,
       Alert.vAlertResolutionState.StateSetByUserId, Alert.vAlert.RepeatCount, Alert.vAlert.RaisedDateTime, Alert.vAlert.AlertDescription, vManagedEntity.Path
FROM   Alert.vAlert
INNER JOIN Alert.vAlertResolutionState ON Alert.vAlert.AlertGuid = Alert.vAlertResolutionState.AlertGuid
INNER JOIN Alert.vAlertDetail ON Alert.vAlertResolutionState.AlertGuid = Alert.vAlertDetail.AlertGuid
INNER JOIN vManagedEntity ON Alert.vAlert.ManagedEntityRowId = vManagedEntity.ManagedEntityRowId
Where (Alert.vAlertResolutionState = 255)
Thanks to Michael Westergaard for his question about Resolved Alerts....