Understanding P6 Dates- By Ron Winter

"Much Ado about Dates" Understanding P6 Date Information Ron Winter, PSP and F. Burak Evrenosoglu, CCE PSP

Presented at the AACEi Annual Conference, July 1, 2009

More Details about Author : http://www.ronwinterconsulting.com/published.htm
 
1. IntroductionSince its initial introduction in early 80’s, Primavera Project Manager (P3™) scheduling software has been a popular tool used by schedulers, project managers and claims consultants. The construction industry relies heavily on this software to develop, maintain and analyze project schedules. In 1999, Primavera introduced an entirely new Critical Path Method (CPM) scheduling package designed for enterprise-wide project management which changed names almost yearly. P3 remained "P3" while this new enterprise-wide software is now called either P5 (short-hand for Primavera Project Manager™) or P6™ (for Enterprise Version 6.)

Besides a fundamental shift in the way that dates are conceptualized, Primavera Inc’s newest and most powerful scheduling software, P6, has more kinds of useable dates than any other software in existence. The majority of P6 users are unaware of the underlying calculations for new date fields and their usage.

P3 users are frequently confused by the issue of dates when converting to P6. This is partly
because the same company produces both P3 and P6 and partly due to the incorrect assumption that P3 must be an earlier version of the current P6 software. Date fields with similar names in both P3 and P6 behave differently in one than in the other. A plethora of new date fields in P6 create a steep learning curve. A lack of documentation regarding these features creates a potential for real confusion.

This paper discusses the underlying calculations for P6 date fields and their potential uses. It also identifies the issues related to them. For brevity, this paper assumes that the reader is familiar with the P3 date characteristics and deals mainly with differences that an experienced P3 user would understand or expect. Highlights of some of the P6 date issues discussed in thispaper include:

Schedulers are familiar with early and late dates. The whole purpose of CPM is to

calculate the early and late dates so that the criticality of activities can be determined.

P6 and P3 use fundamentally different method to calculate and store traditional CPM
dates.
In addition to the traditional CPM date fields, P6 contains numerous other date fields

that are not included in traditional college courses on CPM scheduling. Planned start/finish dates are confusing to many P6 users. This is because planned dates are neither static like baseline dates nor dynamic like early and late dates once the activity has progressed. Planned dates might end up being your baseline dates,and yet they are not truly a baseline. Planned dates do not always display planned information. In some instances they display budgeted and current information as well. So the question becomes, how do the planned start/planned finish dates come into play for you as a project manager?

Many P6 users are puzzled to see complete activities where early and late dates differ from actual dates. Does that mean P6 calculates early and late dates for completeactivities? If so, total float for complete activities can be calculated. Is this as-built float? So how do the early/late dates come into play for you as a claims consultant?

P6 introduced a new float field called remaining float which is dependant on resource leveling. So how does remaining float come into play for you as an earned value professional or as a scheduler? Flexibility and abundance of date fields can be a benefit to the scheduler in developing the work plan if the scheduler is aware of the underlying calculations and uses them purposefully. 

Similarly, claims consultants must understand the P6 date fields so that they can analyze clients’schedules in their original format, without converting to P3.