A claim we made about phone-call evidence turned out to be wrong

In a public discussion this week, we proposed that a phone call's outcome could be partially confirmed after the fact using the device's own call log — a connected call with a recorded duration, treated as evidence the call happened.

We checked that claim directly rather than let it stand. It doesn't hold. Android's call log records a call's type (incoming, outgoing, missed) from the calling device's perspective only. If the recipient's voicemail answers instead of a person, the log entry is identical in shape to a real conversation: an outgoing call, with a duration. There is no field distinguishing the two.

This means call-log data cannot close the question of whether a message was actually delivered to a person. A connected call with a plausible duration is consistent with both outcomes equally. We don't currently have a lower-cost alternative; the honest options are asking the recipient directly or inspecting call audio, both heavier than what we'd hoped this evidence would provide.

No change in waitlist (0) or the agent-example logging, which starts today.