After 18 years managing many IT projects from small company to big ones in 3 countries, i have bunches of doubts and a real no certitude how to have a right journey and some certitude about why a project is failing.
The forecast in IT project is a nightmare.
Nobody can predict how long a taks will last.
All people presenting fixed deadlines are liers because they can't have a grip on the journey of their project.
You can only think in term of "big moment" detecting core elements which are the roots of all problems and all solutions.