Earlier-growth check, October 11, 2026: N = 4,000 per group, K = 1.90, eps = 0.1
Exploratory: chosen after the coherence-growth test and run on the same saved runs, so not a test.
Question: does the coherence say anything about the growth 200 to 500 time units later that the earlier growth does not? Start by start over t = 2,000 to 6,000; error bars from the starts.
Main version (set before it was run): the earlier growth = the growth rate in each of the 5 windows of 100 time units up to the coherence, held fixed by least squares (a partial correlation).

Coherence now against the growth rate 200 to 500 later (the test's second measure)
                                                      fresh starts (7 to 12)                  earlier run (1 to 6)
  as in the test, nothing held fixed                  -0.2061 (0.0186), below 0 in 6 of 6     -0.2476 (0.0353), below 0 in 6 of 6
  the earlier growth held fixed: the 500 before (main)-0.1610 (0.0279), below 0 in 6 of 6     -0.2223 (0.0389), below 0 in 6 of 6
  the earlier growth held fixed: the 200 before       -0.1971 (0.0343), below 0 in 6 of 6     -0.2589 (0.0297), below 0 in 6 of 6
  check on the check: another start's earlier growth  -0.1967 (0.0109), below 0 in 6 of 6     -0.1617 (0.0485), below 0 in 5 of 6
  starts, main version: fresh -0.19, -0.22, -0.05, -0.08, -0.24, -0.19; earlier -0.31, -0.21, -0.04, -0.30, -0.19, -0.29
Reading (main version, fresh starts): still there: coherence says something about later growth that the earlier growth does not
Earlier run, main version: still there: coherence says something about later growth that the earlier growth does not

The growth's own link: the growth rate over the 200 before against the growth rate 200 to 500 later (below 0: growth slows by itself after a burst)
                                                      -0.0558 (0.0329), below 0 in 4 of 6     -0.0234 (0.0318), below 0 in 3 of 6

In the test's windows of 200, one regression per start: growth in a later window = a + b x coherence + c x growth, both in the window
  the next window: coherence and later growth, plain  -0.3694 (0.0537), below 0 in 6 of 6     -0.3433 (0.0776), below 0 in 5 of 6
  the next window: the window's own growth held fixed (b)-0.5480 (0.0545), below 0 in 6 of 6     -0.5421 (0.0487), below 0 in 6 of 6
  2 windows on: coherence and later growth, plain     -0.4978 (0.0730), below 0 in 6 of 6     -0.5659 (0.0616), below 0 in 6 of 6
  2 windows on: the window's own growth held fixed (b)-0.5041 (0.0880), below 0 in 6 of 6     -0.6230 (0.0425), below 0 in 6 of 6
  scaled weights, the next window, fresh: b (coherence) -0.53, c (growth) +0.53 (averages over the starts)
  scaled weights, the next window, earlier: b (coherence) -0.53, c (growth) +0.56 (averages over the starts)

The link at chosen lags L (time units), averaged over the starts: nothing held fixed / the main version held fixed
                           5              50             100             200             300             400             500
  fresh       +0.281/+0.235   +0.112/+0.059   -0.037/-0.079   -0.195/-0.200   -0.198/-0.162   -0.210/-0.142   -0.214/-0.146 
  earlier     +0.291/+0.213   +0.115/+0.033   -0.007/-0.064   -0.179/-0.189   -0.224/-0.201   -0.264/-0.235   -0.308/-0.259