  Simultaneous translation is a task in which the translation begins before the
end of an input speech segment. Its evaluation should be conducted based on
latency in addition to quality, and for users, the smallest possible amount of
latency is preferable. Most existing metrics measure latency based on the start
timings of partial translations and ignore their duration. This means such
metrics do not penalize the latency caused by long translation output, which
delays the comprehension of users and subsequent translations. In this work, we
propose a novel latency evaluation metric for simultaneous translation called
\emph{Average Token Delay} (ATD) that focuses on the duration of partial
translations. We demonstrate its effectiveness through analyses simulating
user-side latency based on Ear-Voice Span (EVS). In our experiment, ATD had the
highest correlation with EVS among baseline latency metrics under most
conditions.
