Estimating how much work there is in the project, and how long each part of it will take, is a vital skill in project management. You can’t sensibly manage a project without having at least some idea of how long you think each piece of work will take!

But, of course, it’s practically impossible to sit down at the start of a project and pronounce when it is going to finish. Issues crop up, the environment changes, tasks take longer than you thought, and so on.

I’ve already written about the scheduling process for a project. This should help you arrive at a list of tasks. These are your starting point for estimating.

Because you have a list of tasks, you are able to begin estimating the length each one will take. Immediately, this is more useful than trying to estimate the length of the entire project, or major sections of it. Bringing your thinking down to the level of specific tasks makes it much easier to mentally grab hold of the work, and have a sensible idea of how much time is involved.

(This also works as a sanity check on your task list – if you can’t visualise what has to be done to complete a task, maybe you need to break it down a little more.)

Remember, you are not necessarily the expert on how long the tasks will take. You have a project team who will actually be doing the majority of the work – use their expertise and their knowledge of both the work and themselves to come up with estimates of how long each task will take.

And don’t forget: you’ll have these estimates wrong. I’ve been using the word “estimate” in this post, but don’t forget the simpler version – “guess”. Yes, you are using experience and knowledge to try and make it a reasonable guess, but it still is one.

It’s a fact of project management life that at the start of a project the estimates will be off. The reason I suggest only scheduling in detail for a few weeks in advance is that you can learn from how far off your estimates are. The accuracy of your estimates should improve as the project goes on.

What about you? What techniques do you use for estimating? Let me know!