Policymakers, despite recent progress, have an incomplete understanding of human behaviour.

The major causes of chaos on a project include incomplete understanding of project components, incomplete understanding of component interactions and changing requirements.

They attribute the lack of improvement in intensity forecasting to the complexity of tropical systems and an incomplete understanding of factors that affect their development.

In part this was due to an incomplete understanding of the sometimes non-obvious force of friction, and a consequently inadequate view of the nature of natural motion.

I do not mean in sensational adventures but in rather odd and difficult personal relationships largely due to their family background and their incomplete understanding of their own natures.