Baseline Duration Graph  (mike vergis - 03/18 22:44:07)

Make a Baseline Graph that is based on Original Durations for construction activities only in order to track progress.
After creating a construction baseline schedule or asked to analyze another scheduler?s baseline construction schedule, I always create an Original Duration Graph as a first step. It is quite simple to do, but can be a little tedious. However, the benefits of preparing such a graph are immense to say the least. It provides a visual illustration to evaluate a schedule?s perceived progress for the duration of the construction project. There may be others, who do this, but I have not ever seen any such graphs. So, I will describe my method for preparing such a graph and anyone, who has done something similar, I would like to know and find out whether or not the value it has to you.
1. First step is to create a baseline schedule with original durations that you and others can believe. Make detailed, but not overly detailed, activities that limit ODs to 1 to 25 or so workdays. Occasionally, there are special activities that will have ODs greater than 25.
2. If your schedule is a pure construction schedule, you are ready to start. If your schedule has milestones, engineering, procurement, testing, inspections, oversight, commissioning, punchlist, or other non-construction activities, you must prepare an activity code in order to filter the construction only activities. This is important. If you have any question whether an activity is a construction activity or not, then simply do not code it. You are determining construction progress and nothing else.
3. Sort the construction activities by the Start Date (Early Start). Do not Group the activities.
4. Select-All and copy/paste the activities to an Excel spreadsheet. This is the Table Data from which a graph will eventually be determined.
5. The Table should contain the following columns: the Activity ID, Activity Name, Start Date, Finish Date, and Original Duration.
6. Adjacent to the Data Table and in the Title row are the monthly duration columns. Enter the first month of construction and run the monthly column titles to the last month of the construction period. Example #7
7. Act ID-Name-Start-Finish-OD-June16-July16-Aug16-Sep16-Oct16-Nov16-Dec16-Jan17-ETC
8. The Act ID, Name, Finish are information data; Start and OD determine the table input data that will determine the duration graph.
9. For each activity line, enter the OD under the appropriate month and if the OD spans two or more months, enter the workdays in the appropriate column. Be sure to enter the workdays and not the calendar days. Some months have more workdays than other months and some months will have non-work holidays that have to be considered. Example #10
10. If an activity has 20 workdays that spans two months; then a portion will be in the startup month and the remaining will be in the following month: Example is 20 workdays with 3 workdays in Jan2017 and 17 workdays in Feb2017. Now if the duration was 30 workdays; then 3 workdays in Jan2017, 20 workdays maximum in Feb2017, and 7 workdays in Mar2017.
11. Enter the appropriate number of workdays for each activity in the appropriate monthly column.
12. When all the activities have their monthly OD workday assignments, calculate the totals at the bottom of each monthly column. Use the SUM formula to calculate all the workdays assigned to each month. Note: the summation line is a formula driven response in each cell. It is a good idea to copy this line and underneath it paste the hard total number in each cell.
13. Underneath each of the total of monthly ODs use a formula that will calculate the percentage of each total OD. Total all the ODs from the first month to the last month and divide each monthly total by the grand total to arrive at a percent per month.
14. You now ready to make a graph that has a y-axis in percents, 0% to 100% and an x-axis that has all the months of the construction period.
15. Make a Graph Table in a vertical format with the Month Column and the OD Percent Column. Next to the table setup a line graph from one of line chart selections offered by Excel, which will automatically plot your Project Duration Graph.
16. This will be your Construction S-Curve graph for the Baseline schedule. Do not expect a smooth perfectly formed S shape. Whatever odd shape is determined, it is your S-curve.
17. With this Baseline S-Curve Graph, you can add another data column and plot another graph with actual physical percents per month to track progress and compare with the Baseline Graph.
18. Include on the same graph an average per month completion rate for the entire period. In other words, if your project is 20 months, then the average is 5% per month. This S-Curve is a straight line.
19. Also, make a graph based on your personal best guess for monthly physical completion. This graph should be the more familiar S-Curve. The data used is your anticipated progress and based only on your personal best guess. I refer this graph as the Anticipated Graph.
When all this is completed, there should be three graphs: 1) the Duration Graph, 2) the Average Graph, and 3) the Anticipated Graph. The fourth, the Actual Graph, is a work in-progress graph that has monthly entries in order to gage progress and compare to the other three static graphs. Calculate the physical percent complete for each month. Make the entry in the appropriate month and see how the Actual Graph compares with the other three graphs.
As long as the Actual Graph has calculated physical percent that tracks above the Anticipated Graph, your project is on time. If it dips below the Anticipated Graph, your project is not on time. The Original Duration Graph is not crucial; except that it is a reality check on the baseline schedule logic paths as it compares with the Actual Graph. The Average Graph has many possibilities, but only three of the many can be correct percentage results: 0% and 100% and the eventual crossover percent. The principles of the S-Curve are integral to the function of the Average Graph because of acceleration and deceleration work-rate monthly percent complete calculations. Construction projects start out with physical percent completes that are below average. As the progress continues, more and more resources are applied that naturally accelerates progress to a crossover point. A bend in the slope of the actual graph begins the deceleration process that has percent completes that are higher than the average. The higher physical percent averages continue to the end on the construction process.
The Anticipated Graph and the Duration Graph should have a ?crossover? point with the Average Graph. Usually, this point is approximately at the 65% to 75% completion point. The crossover point normally begins the deceleration of the physical percent work and the deceleration continues to the end of the construction period. If the Actual Graph does not crossover at some point, your project is falling behind schedule and will required more resources, manpower and equipment. The Actual Graph?s crossover point may end up at the 100% mark, which means, the contract completion date is met. If the Actual Graph?s slope is such that it is projected beyond the 100% completion, the contract completion date is not being met.
The 100% construction completion may not be the Project Completion. The argument point here is ?What is the accepted contract completion date?? Is it Substantial Completion, Beneficial Occupancy, Commissioning Period, Punchlist Period, or whatever? That is your dilemma! When the Original Duration Graph reaches 100%, it has done its job.
   
   

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