W3_Murtadha_Schedule Estimation Analysis (@RISK Simulation Software)

  1. Problem Definition

On my previous blog posting, an analysis on schedule estimation was carried out. The Three point Estimation was carried out to compare the outcome with the project duration of 11 months set by the client.

For this blog posting an additional analysis was carried out using @RISK Simulation Software and a comparison between the two will be conducted and analysed. 

  1. Feasible Alternatives

In this analysis we will be looking at a comparison between two different results achieved through different methodologies for the three point estimation.

  • Using manual calculation as done in W2 Blog
  • Using @RISK Simulation Software
  1. Develop the outcomes for each alternative

Because we are looking at a comparison of two results the two different outcomes are as follows.

  • Matching results confirming the manual calculations
  • Different results invalidating results from manual calculations
  1. Acceptable Criteria

For comparison purposes the acceptable criteria for this analysis will be similar to that of the W2 blog posting which was set as a duration estimate accuracy >90% .

  1. Analysis and comparison of the alternatives

Using the same set of data used in my W2 Blog Post we achieved the following results:

@RISK PERT Analysis

Figure 1.

Comparison between alternatives:

Time ( Months) Manual @RISK
Min 10 10
Average 12 12
Max 14 14
Mean 12 12
sigma 0.667 0.756
Variance 0.444 0.571
P(90) (z=1.29) 12.73 13.01
P(80) (z=0.85) 12.43 12.69


  1. Select the preferred alternative

Based on analysis result, we can see that the results obtained by the simulation software are slightly larger for the P80 and P90 but still are very similar confirming the results obtained in W2 Blog were correctly estimated.  Although the software results must be considered as more accurate.

  1. Performance Monitoring & Post Evaluation of Result

Additionally the simulation gives us additional data that could also be used. The @RISK PERT Simulation also shows that we have a 95% chance of completing the project in 13.2 months where as we only have a 10% chance of completing the project within the project duration set by the client of 11 months.

Similar recommendation as W2 Blog post is advised here, the schedule to be analyzed a number of times as time goes by and as more information is available to get more accurate results.



  1. Estimating Time Accurately: Calculating Realistic Project Timelines. (n.d.). Estimating Time Accurately. Retrieved June 12, 2014, from http://www.mindtools.com/pages/article/newPPM_01.htm
  2. Six Methods for the Estimation of Activity Duration in Project Management. (n.d.). Small Business. Retrieved June 12, 2014, from http://smallbusiness.chron.com/six-methods-estimation-activity-duration-project-management-41782.html
  3. A guide to the project management body of knowledge (PMBOK guide) (5th ed., ). (2013). Project Time Management. Newtown Square, Pa.: Project Management Institute.
  4. Martin, D. (2014, March 25). Estimation Part 2 – Accuracy vs Precision. . Retrieved June 12, 2014, from http://www.dontpanicitsolutions.com.au/lean-thinking/53-estimation-part-2-accuracy-vs-precision/53-estimation-part-2-accuracy-vs-precision
  5. Spent, D. (n.d.). Estimate Activity Durations — PMP Primer. PMP Primer. Retrieved June 12, 2014, from http://www.pm-primer.com/estimate-activity-durations/
  6. ModelAssist for ModelRisk. (n.d.). ModelAssist for ModelRisk. Retrieved June 16, 2014, from http://www.vosesoftware.com/ModelRiskHelp/index.htm#Distributions/Continuous_distributions/PERT_distribution.htm
  7. @RISK: Risk Analysis Software using Monte Carlo Simulation for Excel – at risk – Palisade. (n.d.). @RISK: Risk Analysis Software using Monte Carlo Simulation for Excel – at risk – Palisade. Retrieved June 16, 2014, from http://www.palisade.com/risk/?ad=G_@R-8&gclid=CjgKEAjwq_qcBRDZ-PeZ7NGQiVwSJAATT7q2qqkYyV95YW2Uw5ibRhlCqOMg8j4BCCHRdqW7SZn62fD_BwE
  8. GAO schedule assessment guide best practices for project schedules (Exposure draft. ed.). (2012). Washington, D.C.: U.S. Govt. Accountability Office.



One thought on “W3_Murtadha_Schedule Estimation Analysis (@RISK Simulation Software)

  1. AWESOME posting, Murtadha!!!

    Great case study, you followed our 7 step process correctly and your citations were spot on….!!!

    Doesn’t get any better than this!! Keep up the good work and looking forward to seeing more postings of this quality in the coming weeks!!

    Dr. PDG, AACE Annual Symposium, New Orleans, USA

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