THE FOUR BIG ONES

Let's look at the four big ones first.

Effort (work)

Effort is, quite simply, the amount of work in something. Effort is measured in units such as man-days, man-weeks or man- years . If a person digs a hole and it takes 5 days then the amount of work is 5 man-days. If 5 people dig a hole and it takes them 1 day then that is also 5 man-days.

Schedule (elapsed time)

Schedule is the elapsed or calendar time that something is going to take. Schedule is measured in the ordinary calendar units of time: hour , day, month, year. In the previous example of digging the hole, the schedule in the first instance was 5 days; in the second it was 1 day.

Critical path

Critical path is a much misunderstood term . Critical path is the shortest time (i.e. the shortest schedule or elapsed time) in which something can be completed. In the examples which follow, you will see the significance of critical path.

Milestones

Milestones, as originally placed on roads , showed a traveller how far she was from the start or end of her journey. Milestones in projects do exactly the same. They "anchor" the project at particular points in time. They show how much of the project has been completed and how much is still to go.