  In this paper, we introduce a new metric, named Penalty upon Decision (PuD),
for measuring the impact of communication delays and state changes at the
source on a remote decision maker. Specifically, the metric quantifies the
performance degradation at the decision maker's side due to delayed, erroneous,
and (possibly) missed decisions. We clarify the rationale for the metric and
derive closed-form expressions for its average in M/GI/1 and M/GI/1/1 with
blocking settings. Numerical results are then presented to support our
expressions and to compare the infinite and zero buffer regimes. Interestingly,
comparing these two settings sheds light on a buffer length design challenge
that is essential to minimize the average PuD.
