When it comes to the project schedule, we love to incorporate contingency time into the project schedule without necessarily telling you about it. Hiding it is a good strategy because everyone will work towards the same completion schedule. There's two ways to do contingency planning: one is to add additional time in each of the project steps within a given phase, while the other is to give two or three weeks of time at the end of the project or phase (called a “contingency”).
It's kind of a shock absorber that either compresses or doesn't based on prior activities leading into it. My personal preference is to build contingency into each of the tasks – this is because sometimes tasks will be completed quicker than others, providing an even velocity of activities being completed. This approach prevents this dependence on having two weeks at the end of the phase in case we run late. If there's enough activities or activity owners thinking the same thing, then you can go through those two weeks of buffer in no time.
We're able to do some of this as we get into the project, especially when we know that finance is sprinting at a hundred miles an hour, but HR is inundated with work so they're a little behind. That allows us to build in some of those buffers based on the knowledge of the groups for activities versus putting that buffer at the end. Keeping this contingency time under wraps keeps people from using it anyway since it’s human nature to take as much time as is available. We want to make sure that we can stay on track for the best chance of a successful go live.
Different areas within an organization move at different velocities due to individual’s workloads or personal schedules. This makes the project plan a high-level roadmap that's always being updated and adjusted, meaning if finance moves faster than HR for whatever reasons during design phase, it's a possibility they'll also move faster during the testing phase too. In a situation like that, you want to give HR more time and have finance doing what they can with their normal time.