*Article is under review and update - please see attached document below for the old article.*
Understanding Project Statistics
If you open a project, on the right side of the screen there is a panel that show all relevant Project Statistics:
This article explains which statistics are displayed and how these are calculated.
Not started
To explain the data within the the Statistics Panel, we have created an example project. Which can be seen below:
We will use the example of a project that is planned Just in Time, with feeding buffers that are also planned Just in Time.
The statistics we can take away from the first view:
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Milestone:
- Task 7: Installation shows an orange diamond, which means that this tasks has a deadline. So, it should be finished before that date.
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Duration (1st):
- The difference between the Project Start and the Project End.
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Duration (2nd):
- The difference between Scheduled Start and Scheduled Finish.
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Project Start vs. Scheduled Start:
- Depending on the preferred scheduling engine. Lynx will schedule the tasks As soon as possible or Just in Time. In this case, the tasks are scheduled Just in Time, so the tasks are scheduled from the End date of the project to the left.
- The Project Start is the current date (green line), while the Scheduled Start is the 21st of July, the day on which the project should start.
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Project End vs. Scheduled finish
- The (scheduled) Project end is the same as the input which you have given within Project Properties -> Project Dates -> Project End Date. The Project end is shown by the end of the white/grey area or the start of the darker blue area on the right. In this example we added the red line to highlight the end date. In this case, the Project End date was set on a Saturday 21st of September, which is a non-working day (weekend). Therefore, the Scheduled End date is the day before; Friday 20th of September.
- The difference from Project End and Scheduled Finish:
- If a project is delayed, the end date of a project would still be the the same, but Lynx will calculate the date when it should be finished. This calculation is based on the tasks (durations) that need to be completed, giving the Scheduled Finish.
- If this project would be scheduled As soon as possible, the project would be scheduled from the start date (in this case today) to the right. In that case the Project End will still be determined by what you've scheduled as the end date, but the Scheduled Finish will be calculated from the current date until the date when all tasks are finished. See figure below:
Adding buffers (CCPM Parameters)
When the scheduling of project has been completed, we can add buffers to the project. Use the plus button next to CCPM and use the preferred CCPM Parameters. In this example, all percentages are 50%. Meaning, in short, that 50% of the total task duration is added to the project as Milestone and Project Buffer. For more information about buffers: Add buffers and CCPM behaviour to your plan
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Longest path vs. Critical chain:
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Changing the view:
- The easiest way to check the difference between the Longest path and the Critical chain is to change the view of the project. If you select the Project Buffer and there is resource contention, this will be highlighted by a bold text. This caused the longest path to change, making this project 5 days longer.
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Resource contention:
- In the original plan you can see that two tasks with the System Tester are planned in consecutive order, because there is only 1 resource available with this skill. When you would have two resources with this skill, these tasks could be performed in parallel, which would save you 5 days in this project.
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Changing the view:
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Released
After the project has been released, additional information is added to the the Project Statistics.
Project Buffer Statistics
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Expected Finish:
- In this case the date is the same as the original Project End Date. This has to do with the percentage that has been implemented within the Project Execution. Within this example the Expected Buffer consumption is 100 percent. Which means that you expect that all buffer that has been added will be consumed.
- See paragraph Expected Finish Calculation for some examples of the calculation of the expected buffer consumption.
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Due date performance:
- This the difference between the Scheduled Start till the Scheduled Finish is compared to the Scheduled Start till the Expected Finish.
- Scheduled Start - Scheduled Finish: 51 days.
- Scheduled Start - Expected Finish: 70 days.
- Due date performance: 70 days - 51 days = 19 days early.
- This the difference between the Scheduled Start till the Scheduled Finish is compared to the Scheduled Start till the Expected Finish.
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Current Chain Length:
- At the start of a project the Current Chain Length is most likely to be the same as the Critical Chain, because there have been no progress/ delay.
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Chain Complete:
- This is the percentage of the current longest chain that is completed, calculated by the number of days completed of the chain (tasks completed and expected time - ETTC for Started tasks) compared to the total initial planned duration of the chain.
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Buffer Consumed:
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- This is the percentage consumption of the " Controlling Buffer", in this case the project buffer. Only a Milestone Buffer or a Project Buffer can be a “Controlling Buffer”. Feeding buffers are excluded.
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Feeding Chain:
- This is the length of the feeding chain of the "Controlling Buffer". In this case, it is 35 days.
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Feeding Chain Complete:
- This is the percentage of the feeding chain of the "Controlling Buffer" that is completed. Calculated by the number of days completed of the chain (tasks completed and expected time - ETTC for Started tasks) compared to the total initial planned duration of the chain.
Controlling Buffer Statistics
The controlling buffer is the earliest buffer in Portfolio view. This means it is the most critical buffer in the project. LYNX communicates all key information for the Controlling buffer under "Buffer Consumed", "Feeding Chain", and "Feeding Chain Complete".
Project and Project Portfolio Statistics
In the project portfolio window, you can see the project statistics under the "CCPM" and "Performance" columns.
Depending on which buffer is the controlling buffer, the "CCPM" column will show its data. If the controlling buffer is a milestone buffer, LYNX will show the following data:
- mlc: Milestone Longest Chain
- mc: Milestone Critical Chain
- mpb: Milestone Buffer Penetration
- mb: Milestone Buffer
If the controlling buffer is a project buffer, LYNX will show the following data:
- clc: Current Longest Chain
- cc: Critical Chain
- pbp: Project Buffer Penetration
- pb: Project Buffer
For the "Performance" column, LYNX shows 2 progress bars. The top one is the percentage of the buffer chain is completed, and the bottom one shows the percentage of the buffer is consumed. By default, this is the statistics of the most critical buffer (the controlling buffer). However, you can filter to show all buffers in the project or show different buffers, and sort by priority or by deadline.
You can hover over the bars to see more details.
Measuring Progress
Current Longest Chain (CLC) and Critical Chain (CC)
The CLC is measuring the longest chain during execution phase. Let's consider a critical chain with a feeding task. The current longest chain is the duration of the critical chain. However, let's say as the project progresses, the feeding task is delayed and thus became critical. This would make the current longest chain include the new task, which was not on the original CC.
The critical tasks are shown as red in the Gantt chart. However, you can also see the check box "on critical chain?" in the task details under the general tab.
Expected Finish Calculation
In the project properties, under critical chain, you can set the expected buffer consumption. By default, the value is 100%. The expected finish is the date considering that percentage. It is calculated using the following formula:
Scheduled Finish Date + CLC duration (current longest chain) / CC (critical chain) duration * buffer size * Percentage Expected Buffer consumption
For example, let's take a project with the following values:
- Scheduled finish: 29 October 17.00
- Current longest chain: 35 days
- Critical chain: 40 days
- Buffer size (of controlling buffer): 20%
- Percentage expected buffer consumption: 100%
To calculate how much extra time to add to the scheduled finish date, we calculate:
CLC duration / CC duration * buffer size * Percentage Expected Buffer consumption = 35 / 40 * 20 * 100 = 17.5 days.
Now we add 17.5 days to 29 October 17.00, we get an expected date of 24 November 13.00.
Gaps on the Current Longest Chain
Gaps in the CLC can occur due to:
- Constraints: LYNX calculates and displays a “gap” to indicate that the project potentially can go faster.
- Caused by a Resource Non-Availability period: For example, a resource assigned is on holiday.
- Result of inserting a buffer (e.g. feeding buffer) setting: If the setting "Consume feeding buffers when they extend the CC" is not checked, The feeding buffer is allowed to extend the duration of the Critical Chain.
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