Problem Recognition, Definition, and Evaluation
The new team for AACE class has already completed its 5 days intensive class and formed the team named Simatupang AACE 2014. In regards to prepare the team for long distance class which is has so many tasks that have to be completed, we have to manage our workload effectively to achieve our target. We have done work loading histogram from my previous blog to compare each activity load hours with each baseline 11 hours to do all activities on this course. To get work loading histogram more real, we will apply learning curve to our histogram to see the impact/change. In the last blog, We have exercised the learning curve refers to Engineering Economy books, This time we will try to apply learning curve using Humphrey’s book as reference.
Development of The Feasible Alternatives
Learning curves are applied rigidly in some industries, especially those with high rate production, and completely ignored in others. The basic underlying reason for establishing learning curves is that repetitive tasks should result in improved productivity as the number of repetitions continues to increase.
Development of The Outcomes For Each Alternative
The basic concept of learning curves is that some input resources (e.g., energy costs, labor hours, material costs, engineering hours) decrease, on a per-output-unit basis, as the number of units produced increases. Most learning curves are based on the assumptions that a constant percentage reduction occurs in. Following is equation that be used to compute resource requirements assuming a constant percentage reduction in input resources each time the output quantity is doubled.
Yx = T1x (Xb)
Where Yx = the calculated value of unit X given a first unit value and a slope;
T1 = theoretical or estimated value of the first unit;
s = the learning curve slope parameter expressed as a decimal (s = 0.9 for a 90% learning curve);
b = = the exponential value associated with the slope
Following are the 2 types of learning curves
- Unit Learning Curve
- Cumulative Average Learning Curve
The differences between the two methods above lies in the computation of the total cost of a lot or a production run. Total Cost for Unit Linear will be the sum of the unit costs and that for Cumulative average linear, the total cost will be the unit value times the total number of units up to that point.
Selection of Criteria
We calculate cumulative average time for blog posting activity using Engineering Economy methods (see my previous blog) and Humphresy’s method to get comparison between these 2 methods
Fig 1: Table Calculation Blog Posting Activity using Humphrey’s Method
Fig 2: Cumulative hours Blog Posting using Humphrey’s Method
Fig 3: Table Calculation Blog Posting Activity using Engineering Economy Method
Fig 4: Cumulative hours Blog Posting using Engineering Economy Method
Analysis and Comparison of The Alternatives
Both methods above have a similar calculation result for cumulative unit linear, the differences is happen when we are calculating cumulative average linear as shown on Fig 6.
Fig 5: Workloading Histogram using Learning Curve equation
Comparison of total hours to do long distance course using initial plan, applying learning curves with EE Methods and Humphrey’s method as follows:
Fig 6: Total Hours comparison
Selection of The Preferred Alternatives
Based on Table comparison above, we get information that:
- Applying learning curve into our estimate will be reduce total hours from the initial plan (235)
- There is no differences between EE Methods and Humphreys method for Cumulative Unit Linear
- Cumulative average linear with using EE methods have a greater number of hours than Humphrey’s
Performance Monitoring and Post-Evaluation of Results
Applying learning curve is giving our estimate more reasonable due to in reality, by performing repeated activity, it will increase our work efficiency and productivity. The significant difference between cumulative liner and cumulative Average Linear as shown on table above is a warning that we must be careful as to which method to use (Cumulative linear or cumulative average linear).
Humphreys, Gary C. (2002), Project Management Using Earned Value. 2nd ed., USA: Humphreys & Associates, Inc.
Sullivan, WG., Wicks, EM., Koelling, CP. (2012). Engineering Economy Fifteenth Edition P86-89.
Syafri, AF. (2013, September). W2_AFS_Workloading Histogram. Retrieved from https://simatupangaace2014.wordpress.com/category/postings-by-authors/a-fahmi-s/
Syafri, AF. (2013, September). W3_AFS_Learning Curves. Retrieved from https://simatupangaace2014.wordpress.com/category/postings-by-authors/a-fahmi-s/
Giammalvo, PD. (2013). AACE Certification Preparation Course. Retrieved from http://www.build-project-management-competency.com/
Angeli, E., Wagner, J., Lawrick, E., Moore, K., Anderson, M., Soderlund, L., & Brizee, A. (2010, May 5). General format. Retrieved from http://owl.english.purdue.edu/owl/resource/560/01/