Project 2000. Entering Assignments, страница 7

The way that changes at the assignment level affect contour segments of edited assignment contours in Microsoft Project 2000 is detailed in the following table. There are three distinct scenarios for edited contours when making changes at the assignment level. They are as follows:

Changes at the Assignment Level

Reaction of Contour Segment Lengths

DD, DU

Segment lengths recalculated, proportionality maintained.

DD, DW

Last Segment Extended/Truncated

DU, DW

Segment Length doesn’t change.

Example

Let’s look at an example that shows some of the possible changes and calculations. Suppose we had a Fixed Units task with a three-day duration and that we edited the assignment contour as shown below.

Day One

Day Two

Day Three

38%

88%

50%

3.03h

7.03h

4h

If we increase the assignment units from 88% to 100%, we get a timephased assignment information as shown in the following table:

Day One

Day Two

Day Three

50%

90%

36%

4.02h

7.17h

2.9h

At first glance, it may appear that Microsoft Project is randomly changing our assigned units. In fact, however, it is being very consistent in how it maintains our assignment contour. Because the task is a fixed units task and we are changing units at the assignment level, duration must be recalculated. From our table on page 83 we know that this will cause contour segment lengths to change, but their proportionality to be retained.

This gives us a situation where our timescale units (days) overlap our contour segments as shown in the following table:

Day One – 50%

Day Two – 90%

Day Three – 36%

Contour One –42.94%

Contour Two – 100%

Contour Three – 56.5%

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

Now let’s look at how Microsoft Project makes the exact calculations to come up with the scenario shown in the above table. The first thing that Microsoft Project does in this situation is calculate duration. To do this, Microsoft Project first calculates the assigned units scaled average (Usa) for the edited contour by using the following equation:

 

Where Usa is the units’ scaled average, ∑U is the sum of all of the segments’ units, and Ns is the number of segments.

Contour segments units are [please review this] usually not the units for the assignment during a period of time. In other words, Us does not usually correspond to the % allocation values found in the time-phased portion of the Task Usage view. Rather, Us values correspond to the values shown in the definition tables for predefined contours. In equation form:

Where Us is the units for the contour segment, %A is the % allocation for the time period and Ua is the units for the assignment.

In our scenario, calculating the Usa value gives us the following:

  -OR- 

When segments are of unequal duration, Usa should be calculated as follows: