Project delays: why good software estimates are impossible
If I am running a business that is looking at what projects to fund for the next year, and one of those projects is a software project with an unknowable time to completion vs (for example) opening a new store, with a well known time to complete, why would I ever pick the software project? It has a completely unknown ROI! If you cannot even give me probabilities, the lottery is a more guaranteed investment!Software estimation is required for real business to ever consider software projects. The key is to embrace uncertainty, and instead of estimating that task X will take exactly Y days, estimate a range of possibilities. I like the three point system, estimating a best case, worst case, and most likely case. It explicitly asks you to think about the long tail for when things go wrong. Then use statistical methods to combine estimates and create estimates for multiple confidence levels.This is all covered in a great book, "Software Estimation: Demystifying the Black Art" (https://read.amazon.com/kp/embed?asin=B00JDMPOVQ&asin=B00JDM...). It's not that long a read, and it goes over the problems covered by this blog post but doesn't throw it's hands up in the air and say estimation is impossible.