Why is the canons of proportions on teenagers to estimate height not as accurate as it is on adults?

The canons of proportions, which are guidelines based on body measurements, are less accurate for teenagers because their bodies are still undergoing significant growth and change. During adolescence, factors such as puberty, genetics, and nutrition can lead to variations in growth patterns that deviate from established norms. Additionally, teenagers may not have reached their final adult proportions, making these estimates less reliable. As a result, their body proportions can vary more widely than those of fully developed adults.