Comparison – Page 2 – The Official Site for Zümmer – CPM Schedule Analysis & Comparison

Documenting Progress Data

The Progress Data report is used to identify those activities that have “Progressed” in the “Modified” Project when compared to the “Control” Project. In Zümmer, activities are said to have “Progressed” when any the following events occur:

1)            An Actual Start is achieved;
2)           An Actual Finish is achieved;
3)           The Remaining duration of an ‘In Progress’ activity is reduced;
4)           The Remaining duration of an ‘In Progress’ activity remains the same and the Percent Complete is increased.

It is important to note that other sources, experts, or organizations may define “Progress” based on varying criteria, however, in general, the above 4 conditions cover the vast share of events.

The Progress Data report does not include activities that are considered “non-progressive” revisions. In general, these include:

1)            Added or Deleted Activities;
2)            Changes to Original Duration without a reduction to Remaining Duration;
3)            Increases to Remaining Durations;
4)            Unchanged Remaining Duration without an increase to Percent Complete.

This report is particularly useful in documenting the Progress Only activities when creating or investigating “Half Step” schedule updates.

The Progress Data report combines the following Zümmer:
[15] In-Progress Tasks With Reduced Remaining Duration
[31] Actualization Report (except for added activities)
[33] Increased Percent Complete (where the Modified Remaining Duration is equaled to or greater than the Control Remaining Duration).

In the illustration below, activities shown are considered “Progressed” because:

Line Item #1: Activity’s remaining duration decreased.
Line Item #2: Activity has completed.
Line Item #3: Activity has started.
Line Item #4: Activity’s remaining duration has remained the same, yet the % Complete has increased.

Determining Added or Deleted “Driving Path” Activities

Regardless of the settings for Project->Define Critical Activities:

(a) Total Float less than or equal to; or

(b) Longest Path,

…after a schedule calculation, P6 will mark certain activities on the ‘Driving Path’. The term ‘Driving Path’ is not defined in P6, however, upon observation of the internal database table “Task”, the field name “Driving_Path_Flag” is set to “Y” for activities that are on the longest overall path as shown below.

Changes to the Driving Path between Project updates are possible, however, in P6, those changes are difficult to determine without first assigning a Project as a baseline.

In the illustration below, The Original Duration for Activity “LH930 – Paint Building Interior” was increased from 30 to 35 days causing the activity to fall on the Driving Path. Consequently, 3 activities were removed from the Driving Path.

Zümmer reports these changes in Comparison Reports #22/23 – Added/Deleted Driving Path Activities. Shown Below:

Comparison Report #22 – Added Driving Path Activities

Comparison Report #23 – Deleted Driving Path Activities

Tracking & Reporting Logic Changes

Tracking logic changes can be a nightmare, especially when it comes to large CPM networks with ever changing scope and conditions. Many schedule specifications require that for each logic change, a description for the basis of each change is provided and specifically identifying the affected activities by Activity ID. In other words, the Owner is not just interested in what changed, but more so, why the change was made. Making matters worse, typically each change requires an individual explanation.

Zümmer provides you with seven (7) Comparison Reports designed to neatly account for every logic change between Project Updates.

1&2) Comparison Reports #06/07 – Added/Deleted Logic – These reports list and total the added/deleted logic changes between the Control and Modified Project ID. The reports sort by Predecessor Activity ID.

3) Comparison Report #10 – Added/Deleted Predecessors by Activity ID – groups predecessor logic changes by Activity ID. The action taken, Added or Deleted Predecessor, is coded as AP or DP. The total count is the sum of Reports #06 and #07.

4) Comparison Report – Added/Deleted Successors by Activity ID – is the same as Comparison Report #10 except the action taken, Added or Deleted Successors, is coded as AS or DS. The total count is the same as in Report #10.

5) Comparison Report – Changed Logic By Activity ID – (Illustrated Below) combines the Added/Deleted Successors report with the Added/Deleted Predecessors report. Since every logic change affects activities in pairs (the predecessor and the successor), this report provides an excellent reference document identifying each activity and all the logic changes affecting it.

6&7) Comparison Report – Changed Logic that Increases/Reduces Total Float – Are subsets of Item #5 above.

The Change Logic by Activity ID reports also displays, added/deleted activities, status indicators, and Total Float values.

Reporting & Monitoring Comparison Variances

If a Schedule Comparison is a valuable tool for maintaining high-quality CPM networks, then the next logical step is to monitor and report on the progress of comparison results as schedule updates are submitted on a periodic basis.

For example, if you’re an Owner’s Representative and are receiving monthly schedule updates from a Contractor, then monitoring and reporting comparison results is a great way to ensure high-quality CPM networks are consistently submitted.

In Zümmer, any 2 Schedule Comparison runs can be compared and checked for variances. In the illustration above, a comparison was performed between Update 03 and Update 04, and then later a comparison was performed between Update 04 and Update 05.

Running the Zümmer Comparison Variance report reveals that when compared to the previous comparison, the number of logic changes has increased (+33 for Added Logic and +1 for Deleted Logic).