W14-ABM-Developing the BCWS recovery curve using IEAC

Problem Definition

Further to my Week 13 blog and the development of new baseline schedule, the development of a revised BCWS (early and late curve is required).

The new BCWS curve must assess the extent of balance works and the forecast cost required to complete. To support this process we will now look at the current Estimate at Completion figures and use these estimates to help establish recovery BCWS curves.

Calculating the IEAC can be performed using a number of different methods  and this blog will look at each method and its suitability in supporting the development of recovery BCWS figures/curves.

Feasible Alternatives

EAC data will be assessed at both the Programme and Project levels using the following methods;

  • IEAC1 = ACWP + ((BAC – BCWP) / CPI)
  • IEAC2 = ACWP + ((BAC – BCWP) / SPI)
  • IEAC3 = ACWP + ((BAC – BCWP) / CPI * SPI)
  • IEAC4 = ACWP + ((BAC – BCWP) / ((0.2 * SPI) + (0.8 * CPI))

Development of the Alternatives

Table 01 below is taken from the NDIA/GPC and outlines the assumptions and considerations when using each of the 4 forecasting tools.

Table 01

Each of the techniques will be assessed using project data from Week 13 as per table below. i.e An EAC will be assessed for each individual project / deliverable.

Table 01 – Project Performance Data (week 13)

Selection Criteria

The following criteria will be used to assess the preferred method of establishing the EAC and using to establish a revised BCWS curve for the recovery schedule

  • EAC takes account of Scope which was previously “underestimated” for  and is corrected for balance activities
  • EAC is realistic but also reduces the risk of reporting further increases i.e. pessimistic.
  • Forecast costs accurately reflect the remaining scope

Comparison of the Alternatives

EAC results for each method and level are provided under table 2.0

Table 02 – IEAC Results

The original BAC for all 6 projects was estimated at $20,700 however IEAC calculated using the 4 methods above predict a cost overrun in the range of +20,060 to $62,936 above BAC.

Analysis of these results is as follows

  1. Project 6 – Bid Project:Project 6 is yet to commence and appears to be influenced by a imbalance in ACWP & BCWP figures taken from Week 0 milestone split. CPI and SPI figures for this project are not considered to be reflective of the actual remaining works and it may be more suitable to ignore this section from the EAC calculation and continue to rely on the original BAC.
  2. This imbalance from week 0 split is also observed in projects 2 and 5 where hours recorded within week 0 account for the bulk of current ACWP despite relatively low BCWP recorded. This skews the CPI and SPI figures
  3. IEAC3 – A result of $83,636 is not considered realistic and appears to be influenced by the late starts made on cheat sheet and Bid project (See above).
  4. It can be seen that there is a major difference between the EAC figures calculated at the programme level and those which have been calculated using performance data from each individual project.

Selection of Alternative

From the above, IEAC3 will not be considered as it is not considered realistic and appears to be overly pessimistic.

IEAC 2 is not considered appropriate given the impact of skew to SPI figures due to heavy reliance on SPI and limitations within later part of project.

Whilst IEAC 1 and 4 have produced values which are almost identical in value, IEAC 4 is considered the most appropriate given its partial consideration of SPI ensuring that figures are not overly optimistic.

However adjustment of the Total EAC to account for Project 6 (BID) will be made to take account of unrealistic EAC figures generated when using the reported CPI and SPI figures. This adjustment would be relevant to all options regardless. EAC for project 6 will be based on 100% of BAC.

Finally, to ensure that the accuracy of the EAC is maintained in all areas of the programme, the IEAC will be based on the cumulative EAC value for all 6 projects and not based on the programme level CPI and SPI figures. ($35,186)

With respect to the development of revised BCWS curve, the EAC values to be used are as follows;

Table 03 – IEAC FINAL

Performance Monitoring

Whilst adjustment of BCWS figures is not considered a regular event, the  monitoring of IEAC figures is a continual process and must be undertaken regularly. IEAC4 is recommended for use within weekly reporting against the new BCWS recovery curve.


  1. W09_SJP_Forecasts retrieved 5 November 2107 from https://js-pag-cert-2017.com/w09_sjp_forecasts
  2. Chapter  9.5 – Performance Monitoring Progress – Guild of project controls compendium and reference (CaR) | Project Controls – planning, scheduling, cost management and forensic analysis (Planning Planet).  Retrieved from http://www.planningplanet.com
  3. National Defense Industrial Association. (2014). A Guide to managing programs using predictive measures.



1 thought on “W14-ABM-Developing the BCWS recovery curve using IEAC”

  1. Hi Tony,
    I really think you did a great job on the ANALYSIS!! I hope for your next blog posting that you will try the 5th IEAC method which is to base the EAC on the actual productivity to date? Then project that into the future using PERT?

    I suspect that is going to be the most realistic and perhaps the most shocking results as the productivity simply has not been close to what was originally planned?

    Keep on plugging away Tony….. You are on the right track and should have no problems passing your chosen AACE and/or GPC certificaiton.

    Dr. PDG, back home in Jakarta


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