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Topic History of : SPI below 1.0

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5 years 6 months ago #6261

Brian Mahon

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I know it's likely not news to anybody and there are indeed many more complex details that lie behind EV measurements. However nonetheless if you want to remember that a low CPI or SPI is bad then you just need to realize that P is for performance and low performance is never a good thing.

Works for me!
5 years 7 months ago #6128

Roberto Mendez

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Thanks so much guys, excellent answers :)
5 years 7 months ago #6124

Jonathan Emmons

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One comment on Dawn's answer ... During the course of the project, SPI = 1.00 doesn't necessarily mean that all work is done, as it can also mean that the work is being completed as scheduled (not ahead or behind). When all work is completed, though, the SPI will always equal 1 per Dawn's response (whether or not it came in ahead or behind schedule) since by definition the earned value will at that point equal the planned value for the project.

With regards to Roberto's question - Dawn is correct that the SPI < 1.00 is sufficient to say that the project is behind schedule, and for the purposes of questions you'll see on the PMP exam this is what you need to remember. That being said, in practice, Roberto is right that the critical path needs to be considered as well, as it is certainly possible that your project team is waaaaaay ahead on activities that are not on the critical path, but behind on critical path activities that will be difficult to get back on track, which could lead to an SPI > 1.00 but still run a high risk for finishing late. Similarly, you could be ahead of schedule on the critical path, but have SPI < 1.00 because you happened to schedule several non-critical activities earlier in the schedule that are now dragging down to the index.

So yes, in the real world you'll want to put the SPI into the broader context of what's happening (PMBOK Guide page 219), but again, when you see a PMP exam question that asks what the SPI value tells you, SPI < 1 means the project is behind schedule, and SPI > 1 means the project is ahead of schedule.


One last comment - I don't mean to imply that you'll never need to go with the "not enough information" option on the exam. In particular, you'll need to be careful about questions that mix cost and schedule metrics. Sometimes you'll see a question about schedule where you're given cost metrics (either the CPI itself or the AC and EV values that allow you to calculate CPI), and you really don't have the information you need to answer a question about the project schedule (or vice versa). In these situations, just make sure to review the question carefully and determine what information you need to answer the question being asked, and then see if the question provides that information (or enough pieces that you can get calculate those values yourself).
5 years 7 months ago #6123

Dawn Upperman

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Hi Robert,

No this is not a mistake. The answer is A

Here is additional explanation:

-If the SPI is greater than one, this means more work has been completed than the planned work. In other words, you are ahead of schedule.
-If the SPI is less than one, this means less work has been completed than the planned work. In other words, you are behind schedule.
-If the SPI is equal to one, this means all work is completed

Just having the SPI of 0.97 is sufficient to conclude that the project is behind schedule because the SPI is less than 1.

Hope this helps!
5 years 7 months ago #6122

Roberto Mendez

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Hi All

I came across this question (ID: 25068) in the PMP Exam simulator. I selected Option D as I thought that to determine whether a project is really behind or ahead of schedule, the performance on the critical path needs to be considered. However correct answer was A as indicated below. Is this an error?

Wendy is currently reporting the performance of her project. The project's SPI is 0.97. What should Wendy report regarding the current project performance?

A The project is behind schedule
B The project is ahead of schedule
C The project is on schedule
D The project's performance cannot be determined from the information given

Correct Answer: A


The project's SPI is 0.97, that is 97% completed in comparison to the schedule. Wendy must report that the project is behind schedule.

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