It seems to me that if a child is too short for its age, the repeated threat of the tape measure, together with reminders that everyone else is so much taller, is bound to make a difference.
Children who still stubbornly refuse to grow will cause their schools to come lower in the length table. In extreme cases a school could even be placed under special measurers.
These recalcitrant shorties should be put into STUs (special tallness units). They would be monitored and measured by the SS (special stretching) officers and rigorously prepared for progress in measurement tests (the dreaded PMT).
Peter Tallon 58 Bideford Way Cannock, Staffordshire