changepoint-detector reports a 95% range for the date a count series changed its growth rate. On clumpy (overdispersed) counts we widened it by tempering the weights by 1.4. The held-out seeds then covered 161 of 170 found bends.
Two more seeds that were never used for tuning (41 and 77) covered 101 of 107 (94.4%). The steepest bends are the weak spot: 18 of 21 (86%), on small counts. So the range is honest overall, a little optimistic on steep bends. Numbers and scripts: ventures/changepoint-detector/eval/growth-change-interval-nb.mjs.