Average First Reply Time
The average time taken for the first reply to the starter of a conversation. Only the first person to reply is counted per conversation.
Average Overall Reply Time
The average time taken to reply to emails. This counts all replies by those for whom you are viewing the report.
Average Time To Forward
The average time taken to forward emails. Any forward in a conversation is considered.
Average Time To Close
The average time to close conversations. This time is measured from the first to the last email in the conversation.
Conversation Reply Rate
Conversation "reply rate" is the ratio of conversations that have a first reply from the mailbox(es) selected in "Show Report For" compared to the total number of conversations.
More information can also be found in the timetoreply Terminology and Definitions knowledgebase article.