Forces detailed thinking and planning
This is the biggest benefit! Brainstorming with the team on what needs to be done when and by whom can be a very enlightening exercise. A few months ago I was assisting a project manager and his team as they were developing their plan. As we were loading the tasks into a Microsoft Project schedule (again, could have easily been a napkin), I kept asking about predecessors and successors. This would be followed by a long pause as the team members pondered the concept, then discussion and sometimes, additional tasks would surface. About 3/4 of the way through the exercise the project manager stated "So now I see why we should do it this way!"
A completed / current version of the schedule keeps all team members "singing from the same page of the hymn book". When the team knows what is supposed to occur when and by whom, this makes managing the rest of the project a little easier. Communicating with management, the customer, and other stakeholders is also much easier with a schedule.
Provides a goal
Whether it is the short term goals of tasks for the week, the mid range goals of a deliverable or milestone, or the overall project finish date, this information is all contained within the schedule. And providing you are following the tip of communicating, all team members should be aware of these goals.
Lets you know when you are off track
Just like when you take a trip; the schedule is the roadmap that tells you how to get from point A to point Z. There even may be times when you experience potholes or detours, but if you did not have a roadmap, how would you get back on track? Monitoring the baseline or original schedule allows you to know when you get off track. It will tell you just how far off track your project is, and can allow you to experiment with what-if scenario's for getting back on track.
Reduces delivery time
There are a couple of ways a schedule helps here.
Once your original schedule is complete, you now have the abilitiy to step back and determine what tasks could be started early or completed in parallel with other tasks (Fast Tracking).
Secondly, by tying dates and durations to tasks creates a sense of urgency that might not otherwise be there. Without these dates, a team member may postpone working on an activity that could cause a delay in downstream milestones.
You may think that developing and managing a schedule would increase costs. It is more work right? Here are a few examples of how a schedule reduces cost.
Reduces rework - Imagine someone starting to develop the code for a new application without understanding the requirements.
Eliminates duplicate work - Imagine person A and person B heading off to perform the same task when only person A was assigned.
Return resources sooner - Whether renting a bulldozer, or contracting a team of people, the longer those resources are on the project, the more costly it becomes. A schedule will enable the project manaer to return those resources as soon as possible.
By examining the sequence of tasks and the resources assigned, perhaps periods can be found where resources are under-utilized. Assigning them to additional tasks or changing the logic of when the tasks should be performed will make the team more productive.
See problems early
Whether it is an issue with a milestone date slipping or resources being over-allocated a month from now, having an up-to-date schedule can help you see these problems before they become true issues impacting your project. You can leverage the schedule for what-if scenarios to find a solution or raise the issue to the proper stakeholders well in advance.
Enables project manager to control the project instead of the project having control of them
This one is probably debatable by many project managers who currently have a detailed schedule but still find themselves struggling each day just to stay afloat. But imagine where you would be without that plan!
Hopefully this article has proven some of the value in creating and maintaining a project schedule. If you are currently managing your projects without a schedule, you should try building one and managing to it. It may seem like more work at first, but stick to it. The payoff's come in the long run; I'm sure you will find your life will change. If you do use a schedule, whether it is in MS Project, Excel, or a napkin, look at it now and see how many of these tips you can apply.