All estimates should be accompanied by a "cone of uncertainty". Teams should evolve their ability to describe a cone of uncertainty as well as their ability to estimate. Estimating "accurately" is only possible when understanding the accuracy is elevated to the same importance as the estimate itself.

https://en.wikipedia.org/wiki/The_purpose_of_a_system_is_wha...

https://hubbardresearch.com/product-category/publications/ho...