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P6 Baselines

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According to P6 terminology, a baseline schedule is a complete copy of a project plan that can be compared to the current schedule to evaluate progress.  P6 allows an unlimited number of baselines per project, depending upon administrative preference settings.  Unlike P3, P6 baselines do not exist as separate projects that the user can access unless the baseline schedule is restored and detached from primary schedule.  There are 2 types of baselines Project and User Baselines.  As shown in figure below only up to three user baselines and one project baseline can be assigned per project for comparison purposes.

The user can assign primary, secondary, and tertiary baselines.  User baselines are user specific, meaning that another user opening the project will not be able to see the same baseline unless that user also assigns the same baseline.  If a baseline is not selected, the current project is used by default.  This means that planned dates are used as baseline dates.

If another project is defined as the baseline, then the baseline dates are determined by the Earned Value Calculation option under Admin, Admin Preferences, Earned Value tab shown in figure below.

  • If Budgeted values with planned dates is selected, the baseline dates are equal to the Baseline project’s Planned Start and Finish dates.
  • If either At Completion Values with Current Dates or Budgeted Values with Current Dates is selected then the baseline dates are equal to the Baseline project’s Start and Finish dates.

 There are two ways of adding a new baseline shown in figure below.  Save a copy of the current project as a new baseline saves the current state of the open project as a baseline for the project.  When you save a copy of the current project as a new baseline, the baseline title uses the project name and a suffix of – Bx, where x equals 1 for the first baseline you save for a project, 2 for the second, and so on. The baseline name can be changed.

Convert another project to a new baseline of the current project allows the user to select a different project to use as a baseline for the current project. When you choose to convert another project to a baseline, the project you want to convert cannot be open or have baselines assigned to it. The converted project’s name is used as the baseline name.

Working with Multiple Projects in P6

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One of the big strengths of P6 is its ability to group any number of schedules into a Master Schedule simply by putting the schedules into an EPS.  Opening EPS will open all of the otherwise independent schedules, even if they have mismatched structures.  You can combine schedules that came from other P6 installations, MS Project, SureTrak, P3 and Contractor and consider them all as a single schedule.

In P6 each project can have its own scheduling options.  If multiple project schedules are open and the schedule is calculated, P6 applies the Default Project’s Scheduling Options.  Similarly if multiple projects are open and you add new information to the database, P6 will use the default project’s settings.  When you open multiple projects, users should ensure that they specify the correct default project using “Set Default Project” dialog box shown below.  P6 also uses this project’s leveling settings for calculating the schedule (manually or via the Job Services feature) and it becomes the default destination for new items such as activities or issues unless the layout is grouped by WBS and a different project is selected before adding new items.

 

Set Default Project Dialog Box

 

Another issue with working with multiple schedules arises if these schedules have different data dates.  Each project will be scheduled based on its own Data Date.  The earliest data date of all open projects will be shown as the data date on the Gantt chart. The data dates for individual projects can be changed when applying actual dates but not when scheduling.

New to P6, Service Pack 2 (P6.2) is the option to calculate the total float based on the finish date of each project in a collection of schedules or on all opened schedules.  Previously, when a project containing multiple schedules was opened, P6 calculated the dates based upon the early finish of the last activity in each schedule.  This meant each schedule calculated the critical path independently, even if they were tied together in a network of relationships.  The older method fails to identify the single critical path for a project of multiple schedules.  The down-side of the new option is, other than viewing the scheduling log, there is no indication as to which option was used when later reviewing the results of a CPM computation. On the other hand the Longest Path still only works on one schedule at a time – you cannot produce a multi-schedule longest path.

P6 provides 3 different types of access modes when opening a project, Exclusive, Shared and Read Only shown below.  If the project is opened in shared mode, then multiple users can modify or update the schedule simultaneously.  This results in confusion and it is strongly recommended schedules are opened in Non-Shared access modes.  If the schedule is opened in Shared mode then F5 key must be pressed regularly to refresh the schedule otherwise one person can overwrite another’s changes.

 

Project Access Mode

 

If external relationships are used between projects and if these projects are replaced by importing a new update or a new version of the schedule then the relationships are not automatically recreated.

Another issue with the external relationships is the relationships are lost if only a single project is exported.  In cases like these where the external relationships are lost, P6 attempts to maintain the proper timing by internally constraining the appropriate early/late dates of the activities missing their inter-project relationships.  This causes the schedule to mimic the effects of the relationship at the time of the export.  The imposed constraints will not show up under the task’s constraint boxes, as these are internally imposed.  The only indication of an imposed constraint will be an asterisk printed to the right of the date in the Start or Finish column.  These constraint dates will only be visible in the External Dates columns, if displayed.  To force P6 to ignore such external constraints, the scheduling options tab has a setting for -”Ignore relationships to and from other projects”. This can also fix extreme negative float values.  You can also remove the external constraints entirely from your schedule by showing the External Early Start and External Late Finish columns; remove the external dates shown, and then recalculate the schedule.