Is it possible to report on next and subsequent reply time in Insights?
Next and subsequent reply time are not possible to track in Insights, and therefore prebuilt metrics for it do not exist.
A workaround is to create an SLA policy with a next reply time target for your tickets. In Insights, the SLA Metric Value metric shows how long each target was active on a ticket. You can combine that with the SLA Metric and SLA Metric Instance attributes to see each reply:
It is also possible to calculate custom durations in Insights using timestamps. Insights can only find the first or last time something happened (using SELECT MIN or SELECT MAX with the timestamp), so it is not a good option for ongoing replies. However, it may help you to find specific reply times, like the first reply after a group change.
For some useful recipe articles, visit: Insights recipe: First reply time by event (version 2) and Insights recipe: Duration between two or more ticket events in minutes.
To know more about SLA policies, visit: Defining and using SLA policies (Professional and Enterprise).