Engaged subscribers by weeks since last letter Index at week 0 = 100 · paired cohort soundings +18.6 retained at week 8 Subscriber engagement fades over eight weeks A line chart comparing the old cadence and the tide-letter cadence for retained engaged subscribers from week zero to week eight. 100 80 60 40 20 Tide-letter cadence Old dispatch 58.9 index 40.3 index Week 0 Week 2 Week 4 Week 6 Week 8 Moon marks denote newsletter arrivals; engagement counted as open, save, or paid share within seven days.