Reply time goals can be set up under Tools > Goals.
Here you will have the option to configure a First Reply Time Goal, Overall Reply Time Goal, and Time To Close Goal.
First Reply Time measures how long it takes your team(s) or team member(s) to respond to a new conversation (first email in a conversation thread).
Overall Reply Time looks at the average time it takes to respond to all emails (initial reply and all subsequent replies thereafter).
Time To Close is the time that it takes your agents to close a conversation. For this we look at the total time it has taken between the first message and the last message in a conversation. If only one of your mailboxes linked to timetoreply has been handling the conversation, we use their business hours and time zone. If there have been more than one, we use your company business hours.
In addition to the above reply time goals, you can optionally also set up reply time "bands". If they aren't set, we will use sensible defaults for your reporting.