The single largest factor that will determine the success of a project is whether or not there is a high level of clarity. The concept is simple, yet many project managers struggle, and some stakeholders will not be inclined, to achieve complete clarity. Indeed, the various Project Management methodologies all contain one or more pieces designed to provide project clarity, yet the criticality of this one concept is often misunderstood by even seasoned project managers.
If you are an Executive, a Project Sponsor, Project Manager, Stakeholder, or Subject Matter Expert (SME), if you are on a project and hear that "the details will be worked out later", a blinking red light should be flashing in your head. A detail to one team member may be a significant factor to another. Moreover, a requirement viewed as a detail by a stake-holder may in fact have a great deal of impact in the way that something is designed or built.
If clarity is so important, why does it seem many projects lack this fundamental concept? The answer depends on the project, but often times it simply comes down to a project manager that is not willing to probe. In the absence of a project manager requiring that a team dive into details, they will be left undiscovered until it is to late to prevent them from negatively impacting a project. This can be a challenge for some project managers because it requires being comfortable asking a lot of questions. Unfortunately, many project managers are hesitant to do this because they fear being perceived as unqualified or uninformed on a particular initiative. A great project manager on the other hand embryos what they do not know and uses proving as an opportunity for the entire team to become more educated. In the same way a professor gets a class to learn by asking questions, a project manager can do the same with a project team.
Not surprisingly, a high level of clarity has extremely positive effects on the moral of individual team members as well as the team as a whole. When people have had the opportunity to commit to expectations, know exactly what is expected of them and when it is expected, they are much more likely not only to succeed, but to excel. To illustrate this point, imagine you are asked to go to the grocery store to pick up a few items for two different people. One person gives you a list requiring you to purchase beer, snacks, soda, juice and liquor. The other requests that you get a case of Heineken, 2 bags of tortilla Chips and 1 jar of Salsa, a gallon of Cranberry Juice and a fifth of Vodka. You are of course far more likely to "succeed" in picking up the correct items for the person who provided more detail as there was much more clarity on what they actually wanted.
Now imagine you're an engineer on a multi-million dollar engagement, and the success of the project is going to have an impact on your career. In very short order, you will respect and appreciate a project manager that demands the clarity required for you to do your job effectively. While there is never a single tool that will ensure the success of a project, using many of them to achieve clarity will always help keep a project on track. For all the varying methodologies, theories, and software programs available to project managers; at the end of the day, clarity is king.