Thirty percent transmission is the floor, not the ceiling, of intergenerational harm.
Evidence
The 30 percent figure captured only the most extreme cases: physical abuse severe enough to be court-documented. Beneath that endpoint, the intergenerational signal extended through a much larger distribution of harsh discipline, emotional unavailability, inconsistent caregiving, and household dysfunction that fell legally short of substantiated abuse but fell within the developmental-harm range the ACE questionnaire was built to measure. … The ACE circuit was operating across that full distribution. The visible endpoint — substantiated child abuse — was the apex of a pyramid beneath which sat millions of households in which the intergenerational machine was running at lower intensities but in the same direction. — , The Rod and the Child, 7041