There are many legitimate reasons for a project to go off the rails. But if you don’t get ahead of the issues and communicate your concerns early on, you could be left with a handful of weak excuses—which won’t help you or the project.

From the ebook:

I didn’t understand the assignment
Not every boss has great communication skills. And yes, having a manager who is not good at explaining what needs to be done makes life difficult. At the same time, using your boss’ inability to explain things as an excuse for not doing them just does not fly. If an assignment doesn’t make sense, it’s your responsibility to find out what really has to happen. And if you find yourself in this situation more than once, it’s a sign that you need to be extra careful when working with this particular person to get things fully understood.

The deadline was impossible
We all know this situation: A manager hands you an assignment with a deadline attached to it. You tell the manager that the deadline can’t be met and you’re told, “I don’t care; make it happen.” When the deadline is missed, you say, “But I told you the deadline was impossible!” and the boss is still angry. The disconnect here is that simply saying that the deadline is not possible is not good enough. As soon as the boss tells you to do it and you passively accept the ridiculous deadline, you make it your responsibility to meet it.

Your best defense is to negotiate a better deadline, and to do that, you need a project plan. The fact is, you always should be able to paint a picture of what a project will entail with some broad strokes anyway, and it is fairly easy to assign some rough estimates of the time to make each step happen. When you show your supervisor that even the most optimistic rough draft of a plan that omits a million minor details shows that it will take three months and they are demanding three weeks, guess what? It is now your manager’s responsibility to deal with the deadline issue. You have turned an opponent into an ally, and no sane boss can hold you accountable for the bad deadline anymore.

A valuable resource was not available
A good part of a manager’s job is to ensure that the team has adequate resources in the form of time, money, and equipment. If you are missing a critical resource, your manager needs to know now—not when the project is late or has failed—so that they can fix the problem immediately. When you tell your boss ahead of time, it’s not an excuse. It’s asking for help to solve a problem. When you tell your boss after it’s too late, it becomes an excuse and the failure is on you.