W15_SJP_Tracking and Reporting CPI & SPI

Issue Identification and Appraisal

Back on the course trail again this week, a few weeks back, the task of tracking and reporting Cost Performance Index (CPI) and Schedule Performance Index (SPI) was given. Research has shown there are several ways to graphically represent these two metrics but which one is more informative. This week’s blog problem statement is, “Which CPI/SPI graphic provides the best visual representation to management?”

Feasible Alternatives

Review of the Guild of Project Controls Compendium and Reference (GPC) Module 9.4 ‘Assessing & Interpreting Progress Data’ shows two method/graphics; i) Cost/Schedule Trend Report, and ii) SPI & CPI Tracked Over Time.

The alternatives are:

  • Target chart Graphic
  • Line Chart Graphic

Develop the Outcomes for each

The graphics for both alternatives have been taken from the GPCCAR and are shown in figures 1 and 2 below.

Figure 1: Cost/Schedule Trend Report

Figure 1 is in the form of a “Target Chart” and the CPI/SPI point is plotted as an X-Y chart. Each Quartile has a message to tell, whether it is “Ahead of Schedule/Under Budget” or “Behind Schedule/Over Budget”, along with the grouping of the data points to determine accuracy, precision and reliability.

Figure 2: SPI & CPI Tracked Over Time

Figure 2 is a modified line chart which provides the same information as figure one but the graphic shows separate lines for CPI and SPI.

For this blog, a format was developed for each model to show the comparison of the graphics. However, should either of these be utilized on a live project, it would be expected that the format be developed by the Project Controls Team for use.

Selection Criteria

The criteria selection for both models will be taken from W05 through W14 weekly reports. Table 1 below shows the information to be used.

Table 1: CPI & SPI Data points for use in Analysis

Analysis and Comparison of the Alternatives

Using the data points from table 1, the input for Feasible Alternative 1 “Cost/Schedule Trend Report” was performed providing the following graphical output.

Figure 3: Cost/Schedule Trend Report

Inputting the same information into the Feasible Alternative 2 “SPI & CPI Tracked Over Time” provided the graphic in Figure 4.

Figure 4: SPI & CPI Tracked Over Time

Both figures were developed from the same information but look different. See how the information in figure 3, the target chart not only provides the data points, it also lets the viewer (in this case, but on a project, it would be the project manager) see the accuracy of the information provided, and the precision of the data points which in this case are widely distributed which would suggest that the initial cost and schedule budgets were over generous.

Figure 4 does not impart the same message and if the reader was not aware what he was looking at, would glance at the information and move on. It does not have the same powerful message embedded in the graphic.

Selection of Preferred Alternative

The use of the Multi-attribute decision making process will allow us to build a small model to evaluate the best visual graphic that gets the message across to the reader (i.e. Project Management).

Table 2: MADM Evaluation of Feasible Alternatives

From table 2, the selection of feasible alternative 1 is evident, as the graphic is very powerful and at a glance the reader can determine the status and what needs to be addressed.

The author liked the information provided by the selected graphic that it was recommended as a “Dashboard Page one” graphic in Paper 3.

Monitoring Post Evaluation Performance

Closely monitor the graphic to ensure that it’s use is being effective; the project controller needs to be able to review the graphic in conjunction with remaining float to ensure that the correct assessments are being made, and that management are aware of what actions need to be taken. Ensure that the correct model (feasible alternative) is being used to provide the information and status. Periodically review the graphic and the corresponding write-up to verify accuracy of the information provided.



4 Replies to “W15_SJP_Tracking and Reporting CPI & SPI

  1. Love it…… LOVE IT…… LOVE IT……!!!

    But is there any reason you didn’t include the “Accuracy, Reliability and Precision” measurement in this? Or are you saving that for your W16 blog posting? I think it is really important that people come to understand just how much valuable information can be derived from this relatively simple graphic. The most important part being it provides a really great way to see how “accurate, reliable and precise” our original or baseline time and cost estimates were.

    Keep up the really great work and hope to see you explaining to us how to use this data to benchmark our cost and time estimates.

    Dr. PDG, Jakarta, Indonesia

  2. PS Steve for Figure 4, you may also want to explain what it means to see not only those readings falling outside the upper and lower SPECIFICATION limits but also what it means when you see readings falling outside of the upper and lower CONTROL limits?

    Most importantly when readings fall outside of the upper and lower CONTROL limits what kind of causes does that signify and what are you supposed to do with those readings?

    That alone may make a really great blog posting topic….

    Dr. PDG, Jakarta

    1. I created my own format in Excel using the figure from the GPCCAR as a guide.
      Email me on sjptain@aol.com and I’ll send you a copy once I get home at the weekend.


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