p Chart — Call Abandon Rate
Twenty-one days of abandoned calls against a daily volume that swings from 780 to 1,540, giving stepped binomial limits around a 5.1% centre line and isolating the storm-day spike as the only genuine special cause.
Make it your own.
title "Call abandon rate — support queue"
chart p
unit "fraction abandoned"
# Only the classic four rules: on a daily operational chart the
# zone rules fire often enough to train people to ignore the chart.
rules: 1, 2, 5, 6
sample n: 782 defects: 28
sample n: 968 defects: 52
sample n: 1163 defects: 63
sample n: 1347 defects: 59
sample n: 1541 defects: 78
sample n: 874 defects: 45
sample n: 1062 defects: 44
sample n: 1258 defects: 70
sample n: 1449 defects: 73
sample n: 795 defects: 31
sample n: 981 defects: 48
sample n: 1155 defects: 46
sample n: 1362 defects: 66
# Storm outage — one queue lost its overflow route for four hours.
sample n: 1538 defects: 175
sample n: 866 defects: 40
sample n: 1071 defects: 45
sample n: 1249 defects: 66
sample n: 1441 defects: 61
sample n: 788 defects: 34
sample n: 974 defects: 36
sample n: 1168 defects: 60