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Topics: Earned Value Management, Scheduling
MS Project SPI Calculations confusion
Network:836



Struggling to understand the SPI calculation in my schedule, hoping someone can shed some much needed light on the matter:

I have the following data:

I cant figure out why if the baseline finish is 17 October and the actual finish of the task is 6th November it shows an SPI of 1?


Baseline start Oct 20 '19 Baseline Finish Oct 30 '19
Actual start Oct 20 '19 Actual Finish Nov 6 '19
CPI is 0.56 (meaning we spent more money than we planned by 44%)

Using MS project Online Desktop client
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Network:18



Let me try it this way
"
SPI is not realy about "baseline finish date" and "actual finish date"
It is more a ratio of the value or amount of work done by the amount of work planed (baseline work)
Now considering your problem.
The amount of work that was planned to be finished on the 30th of October which is actualy the whole project work was't finished that day
So if you can determine the amount (value) of work effectively realized that day you will divide it by the planned work (in your cas the whole work) and get the SPI that is less than 1.
your software actualy gave you the SPI at the end of the day on the 6 november and it is 1
Network:2419



Did you update your remaining work?
...
1 reply by Melissa Hellas Tsalicoglou
Nov 06, 2019 1:45 PM
Melissa Hellas Tsalicoglou
...
No more remaining work as the task is complete however SPI shows 1 and task completed after the baseline finish date...
Network:0



Hi Melissa. Like all earned value calculations, SPI is calculated to reflect the project status on a certain date, which in MSP is the Status Date. If the Status Date is after the baseline finish AND the actual finish date of a task, then Earned Value and Planned Value are both 100% of the baseline value, and SPI=1. For your task that finished late, you may see an SPI less than 1 if you reset the Status Date to some date between the baseline finish and the actual finish of the task. (though I would never recommend setting the Status Date backwards as a routine process.
Your example also demonstrates the declining usefulness of EV metrics near the completion of the project.
...
1 reply by Melissa Hellas Tsalicoglou
Nov 06, 2019 1:45 PM
Melissa Hellas Tsalicoglou
...
This comment is very valuable - Your example also demonstrates the declining usefulness of EV metrics near the completion of the project.

Thank you
Network:30093



Follow the Kamwa comments. The application calculates correctly.
Network:877



Hi Melissa, Kamwa is correct
I hope this example will assist…. SPI = EV/PV.
SPI measures the efficiency of the schedule
EV earned value – (work performed - how much did I get done, budget cost)
PV planned value - (the ‘promise’ – how much will it cost, the budget of all work planned)
AC actual cost – (how much it actually cost in reality)

PV – the ‘promise’ was start Oct 20 and finish Oct 30 (10 days) you need the monetary value for each day, for example $100 per day = 10 days @ $100/day, therefore PV ‘promise’ is $1,000
EV – how much work did you get done by Oct 30, example 80% of $1,000 = $800

SPI = EV/PV $800/$1000 = 0.8, therefore behind schedule.

Based on the example value figures your AC would be
AC Actual Cost – how much it actually cost, Oct 20 to Nov 6 (17 days), 17 x $100 = $1,700
...
2 replies by Melissa Hellas Tsalicoglou
Nov 06, 2019 1:55 PM
Melissa Hellas Tsalicoglou
...
So if your Actual cost is now 1700(finish date 6th Nov) and your planned cost was 1000 what would the SPI be? Still 1? Meaning SPI is only used during project tracking when the work is not complete to show if tasks are behind schedule?
Nov 07, 2019 5:36 AM
Melissa Hellas Tsalicoglou
...
@Julie one more situation which shows SPI of 1.14 at 100% completion. I was understanding the when a task is 100% the SPI goes to 1 regardless if its past the baseline finish date
There must be something I am missing the understanding this SPI
Baseline start date 4 Nov and baseline Finish date 10 Nov ( 4 days) The work started on the 5 Nov and ended on 5 Nov SPI is 1.14 at 100% completion
Network:1673



If you have multiple parallel network paths and team members have got ahead on some non-critical path activities, your EV could be greater than or equal to your PV and you could still end up being behind schedule relative to your critical path.

Kiron
...
1 reply by Melissa Hellas Tsalicoglou
Nov 06, 2019 1:51 PM
Melissa Hellas Tsalicoglou
...
Yes indeed, but my confusion is more about the validity of the SPI at the end of a task , which in this case finished later than planned but showed a SPI as 1 which means on track ...though in reality it completed after the baseline finish date...which should show less than 1. In reviewing the comments I am seeing that this is a ratio of work still to be complete ( if I understand correctly) and by the time 6th Nov came the work is complete therefore showing a 1 SPI ( to anyone outside of PM will not understand)
Network:836



Nov 06, 2019 7:23 AM
Replying to Thomas Boyle
...
Hi Melissa. Like all earned value calculations, SPI is calculated to reflect the project status on a certain date, which in MSP is the Status Date. If the Status Date is after the baseline finish AND the actual finish date of a task, then Earned Value and Planned Value are both 100% of the baseline value, and SPI=1. For your task that finished late, you may see an SPI less than 1 if you reset the Status Date to some date between the baseline finish and the actual finish of the task. (though I would never recommend setting the Status Date backwards as a routine process.
Your example also demonstrates the declining usefulness of EV metrics near the completion of the project.
This comment is very valuable - Your example also demonstrates the declining usefulness of EV metrics near the completion of the project.

Thank you
Network:836



Nov 06, 2019 7:10 AM
Replying to Andrew Craig
...
Did you update your remaining work?
No more remaining work as the task is complete however SPI shows 1 and task completed after the baseline finish date...
Network:836



Nov 06, 2019 11:32 AM
Replying to Kiron Bondale
...
If you have multiple parallel network paths and team members have got ahead on some non-critical path activities, your EV could be greater than or equal to your PV and you could still end up being behind schedule relative to your critical path.

Kiron
Yes indeed, but my confusion is more about the validity of the SPI at the end of a task , which in this case finished later than planned but showed a SPI as 1 which means on track ...though in reality it completed after the baseline finish date...which should show less than 1. In reviewing the comments I am seeing that this is a ratio of work still to be complete ( if I understand correctly) and by the time 6th Nov came the work is complete therefore showing a 1 SPI ( to anyone outside of PM will not understand)
Network:836



Nov 06, 2019 9:28 AM
Replying to Julie Ann Jones
...
Hi Melissa, Kamwa is correct
I hope this example will assist…. SPI = EV/PV.
SPI measures the efficiency of the schedule
EV earned value – (work performed - how much did I get done, budget cost)
PV planned value - (the ‘promise’ – how much will it cost, the budget of all work planned)
AC actual cost – (how much it actually cost in reality)

PV – the ‘promise’ was start Oct 20 and finish Oct 30 (10 days) you need the monetary value for each day, for example $100 per day = 10 days @ $100/day, therefore PV ‘promise’ is $1,000
EV – how much work did you get done by Oct 30, example 80% of $1,000 = $800

SPI = EV/PV $800/$1000 = 0.8, therefore behind schedule.

Based on the example value figures your AC would be
AC Actual Cost – how much it actually cost, Oct 20 to Nov 6 (17 days), 17 x $100 = $1,700
So if your Actual cost is now 1700(finish date 6th Nov) and your planned cost was 1000 what would the SPI be? Still 1? Meaning SPI is only used during project tracking when the work is not complete to show if tasks are behind schedule?
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