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LEVEL OF EFFORT vs. WBS SUMMARY ACTIVITY TYPES IN PRIMAVERA P6

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Level of Effort vs. WBS Summary Activity Types in Primavera P6

In Primavera P6 there are six different activity types, two of which are called WBS Summary and Level of Effort (LOE). Both are very useful to determine the dates, duration range, and duration % complete of a group of activities. They are also useful in spreading resources or expense costs over that duration range. Administrative costs, overhead, other non-work task costs and indirect costs can be assigned to these activity types as well.

What is a WBS Summary Activity Type?

  • Summarizes all the activities under a WBS node/element
  • No relationships are used
  • Matches the date, duration and Duration % Complete summary information in the Group & Sort Title bands, if it is “Grouped by WBS” and the “Show Group Totals” is check marked
  • Best practice to use a WBS Summary activity type, because not all layouts will be “Grouped by WBS” which will show the Summary bands
  • The Duration range is calculated from the Early Start Dates to Latest Finish Dates of all the activities within the WBS. From there the assigned Calendar to the WBS Activity is used to calculate the overall duration WBS Activities

What is a Level of Effort Activity Type?

  • Summarizes activities based on the LOE Activity’s assigned Predecessor Activity to its assigned Successor Activity
  • Not restricted to one WBS node, it can span over several WBS nodes.
  • Based on its Predecessor (usually Start-to-Start) and Successor (usually Finish-to-Finish) Relationships. Although LOE Activities can use any type of relationship.
  • Was referred to as a ‘hammock’ in the older version of Primavera P3. A ‘hammock’ is when the Predecessor Activity has a Start-to-Start relationship, and the Successor activity has a Finish-to-Finish relationship with the LOE Activity.
  • The Duration range for an LOE is calculated from the earliest of the Early Start Date(s) of its Predecessor Activities to the latest of the Early Finish Date(s) of its Successor Activities. From there the assigned Calendar to the LOE Activity is used to calculate the overall duration of the LOE Activities.

(**EDITOR’S NOTE: Some activities may show start/finish days that do not align with the original durations. This is an error on our part with assigned calendars. It will be fixed soon. Otherwise, all other information is accurate with the article write-up!) This simple project scenario below illustrates the subtle differences between a WBS Summary activity type to a LOE activity Type:

loe-wbs-1

loe-wbs-2

- Activity M1000 is a WBS Summary Activity Type that automatically summarizes the entire project because of its placement at the top of the project at the Level 1 Project: Project ABC group. Notice how the roll-up values correspond to the blue Project grouping band.

- Activity A1000 is a WBS Summary Activity Type that automatically summarizes all the activities under the Level 2 WBS:ABC.1.1 group which includes Activities A1010 to A1050. Notice how the roll-up values correspond to the green WBS grouping band. This provides the Original Duration (duration range) for the WBS Summary A1000 as 26days.

- Activity B1000 is a Level of Effort Activity Type that summarizes two groups of activities (B1010 to B1050) under two WBS groups (WBS: ABC.2.2 and ABC.3.3). This provides the Original Duration (duration range) for the LOE B1000 as 25days.

 

Why is there a difference of 1 day duration between the WBS Summary vs. the LOE for an identical group of activities?

  • **Remember that in P6 Start Dates are calculated for the beginning of that work day and P6 Finish Dates are calculated to the end of that work day
  • The LOE Activity Type gets its duration from both the Early Start & Early Finish times of the group of activities. Therefore, the LOE gives the most optimistic range the group of activities can start and finish
  • The WBS Summary Activity Type gets its duration from the Early Start & Late Finish time of the group of activities. Therefore, the WBS Summary gives the broadest range the group of activities can potentially start and finish
  • Since it gives the broadest range for the activities to start and finish, the Duration of a WBS Activity Type (ex. 26 days) will not be the same if you literally added all the durations of the activities in the group (ex. 25 days)

The main use of either the WBS Summary or the LOE Activity Type is to help provide summary roll-ups for dates, durations and % complete. They allow flexibility to spread expense and resource costs over a group of activities, whether they all fall under one WBS node, or a select group of activities. Using and understanding either of these activity types can help you further customize your project reports.

The post LEVEL OF EFFORT vs. WBS SUMMARY ACTIVITY TYPES IN PRIMAVERA P6 appeared first on CPM Solutions.


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