Estimating, Not Guesstimating Using Fixed Work, Duration, and Resources

So. We've built our WBS and we've determined our project schedule. Now, finally, we're ready to start putting tasks into the View pane of Microsoft Project.

Dux recommends, in this crash course screencast, that the first task you put in is either a start task or an end task. Aside from that, though, you can put the tasks from your WBS in any order. You'll order these things later. For the moment, just list them off in whatever order you think of them (or whatever order they're in on your WBS, or whatever). Point is, you don't have to worry about the order of your tasks quite yet. Just plug them into the cells in any order in the "Task Name" column.

When I was creating my WBS, I listed things off roughly in the order I needed to do them. But as I was putting my WBS items into Project, I realized that I'd left an important item off my WBS list: selecting dates for the vacation. My impulse, when plugging these tasks into Project, was to go back and add a row so I could put "Select dates of vacation" before "Drive to airport." I don't even know if that's possible, adding a row. It looks kind of like Excel; does it behave like Excel? But I overrode my neurotic need to order my tasks properly at this point, trusting that there is a mechanism later for ordering them, and stuck "Select dates of vacation" (what would be the second item on my task list) between "Drive to airport" and "Park car in long-term parking" (considerably further down on my task list). Because Dux told me that order doesn't matter at this point. This is putting your brain dump (WBS) to paper, and is, at this moment in time, also a brain dump – just into the software rather than on paper.

Once I got all my tasks in, I saved the file with a descriptive name. Because that's just how I roll.

Now, I've got the first two steps of my project done in Microsoft Project 2010. I've defined a schedule and I've put my project tasks into the software. This has been remarkably easy. I'm sure there has to be some big bad something lurking around the corner to make this whole thing a lot more difficult than it has been so far.

Step three is entering estimates for each task. How long is each task going to take, how much work is each task going to take, and how many resources do you have at your disposal to get this task done? You're measuring three things when you put in your estimates: duration, work, and resources.

This is, obviously, a little more involved than just brainstorming all the stuff you've gotta do to make your project happen and throwing it into a table. You have to drill down into each task, and you want to carefully consider the amount of time, resources, and work you're allotting to each task, rather than throwing in some random number to fill in the cell so you can move on to the next thing. If you put in an inaccurate number just to have something, anything filling that field, it's going to throw your whole project off.

Determining the duration and work and resources can be a little bit tricky. It's a whole other way of thinking, a very specialized groove into which to fit your gray matter.

Duration is how long each task is going to take - the starting point, the end point, and the points in between. If the duration of your project task doesn't change no matter how many resources you have or how much work is going into it, this is called, handily enough, "fixed duration."

Work is how much effort goes into making your task happen. It is generally something you can estimate based on previous experience with a similar effort: you know it's going to take you about 20 minutes to shower in the morning, because you've taken countless showers in your life; the work you calculate for the "cleaning self" task is 20 minutes. Work can be varied tremendously depending on how many resources you put into a task. The work estimate is the sum of how much time your resources put into the task: man-hours.  If the work is the same no matter how many people you put on a task, it's called "fixed work."

Your resources are your people working on a task. (Your resources can also be material resources, but for the purpose of this formula, your resources are the folks doing the work.) I know it's going to shock you that if you have the same number of resources assigned to a task, it's called "fixed resource."

For each task, you can only have one fixed thing. If your duration is fixed, your resources and work are fluid. If your task is fixed work, your resources and duration are likely to change as you alter the ratios. And so forth.

It should also be noted that this whole time, I have been talking about estimating for individual tasks, not for the project. When we're estimating the duration, we're estimating the duration of each task, not the duration of the project itself.