Conversation (session boundary)
A run of messages with less than 30 minutes between any two of them — the boundary that separates "a reply" from "starting something new".
A chat export has no built-in idea of where one conversation ends and another begins — it’s just one long, continuous list of messages. Splitting it into conversations requires a rule, and the simplest one that holds up is a time gap: keep going as long as messages arrive within 30 minutes of each other, and treat a longer silence as the end of one conversation and, eventually, the start of another. The number is arbitrary in the sense that 20 or 45 minutes would also be defensible, but it has to be picked and held fixed for every measurement that depends on it to mean the same thing throughout.
Example
Three messages sent at 9:00, 9:12, and 9:25 are one conversation. A fourth message at 10:10 starts a new one, even though it might be a continuation of the same real-life topic.
Frequently asked questions
Why 30 minutes and not, say, an hour?+
Thirty minutes comfortably separates a pause to answer a phone call or finish a task from an actual end to the exchange, without so short a window that a slow typer gets split into two conversations by accident.
Does this match how the people in the chat would describe their conversations?+
Approximately, not exactly — it’s a consistent statistical boundary, not a record of what either person considered a "topic." Use it to compare relative pacing, not as a literal transcript of distinct discussions.
Related terms
- Burst reply timeThe typing-speed number — how fast someone answers while a back-and-forth is already happening, usually measured in seconds.
- Overnight replyA reply that came more than six hours later, crossing the small hours — tracked apart from ordinary reply times because it’s a different thing entirely.