How Does Project Calculate Status

[amc422]

The status column indicates if a task is late, on schedule, future task,
etc., using numeric values. To what do those numeric values relate? I
thought the values related to SPI, but that does not appear to be the case.
The numbering scheme used is:

0 = complete
1 = on schedule
2 = late
3 = future task

SPI values:

Greater than 1 = ahead of schedule
Less than 1 = behind schedule

So what do the numbers on which Project determines whether or not a task is
late mean? Also, how does project calculate this value for rollup tasks?

Many thanks,
Anna

 

[John]

The status column indicates if a task is late, on schedule, future task,
etc., using numeric values. To what do those numeric values relate? I
thought the values related to SPI, but that does not appear to be the case.
The numbering scheme used is:

0 = complete
1 = on schedule
2 = late
3 = future task

SPI values:

Greater than 1 = ahead of schedule
Less than 1 = behind schedule

So what do the numbers on which Project determines whether or not a task is
late mean? Also, how does project calculate this value for rollup tasks?

Many thanks,
Anna

Anna,
Interesting that there have been several questions on the Status field
of late. I guess issues come in droves

The best way to learn about the Status field is to add that field as a
column in the view. Then hover your mouse over the column heading. In a
moment a drop down will show a link to that field's help topic. As far
as the numerical values, Project has an internal algorithm that assigns
a numerical value to the Status field descriptive title. You already
know the code, so nothing magic there.

As far as Status at the rollup level, I haven't studied it extensively,
but as I recall the summary line will show the "worst" condition of its
subtasks. So for example, if all subtasks are complete or on schedule
but one is late, the summary line will show late. And that makes sense,
its kind of like % complete, a summary line will not show 100% until all
subtasks are 100 % complete.

One more comment. In my opinion SPI is a bogus metric, even if it is a
universally accepted classic metric of earned value. It is measured in
terms of cost, not time or work accomplished. Accomplishments to
schedule are not always related to cost. I believe a much better measure
of schedule performance index is through critical path analysis and
total slack.

Hope this helps.
John
Project MVP

 

[amc422]

John,

Yes, that helps a great deal. Thank you very much!

Anna

 

[John]

John,

Yes, that helps a great deal. Thank you very much!

Anna

Anna,
You're welcome and thanks for the feedback.
John

 

[Jim Aksel]

John, I agreee, the arithmetic of SPI requires SPI=1.0 at the conclusion of
a project, even if it is late. That makes no sense.
There is an emerging calculation called "Earned Schedule" which addresses
this topic and allows SPI to remain at a more realistic level and even be
different from 1.0 at the end of the program (or task). hit me at jeaksel at
yahoo dot com if you would like some additional information.