After all, predominant software products support a form of scheduling designed for best productivity and not the original 1956 algorithm designed for fastest completion. There has also been a movement over the past decade to promote enterprise level reporting and central control over empowering (and trusting) individual project managers to weigh the tradeoffs of cost v time on their portfolios of one significant venture at a time. Perhaps this was driven by the failing economy – or perhaps the rush to strip individual initiative and consolidate to central control led the recession.
But the good news is that both startup niche and established players are beginning to consider the needs of the less-than-enterprise sized end users once again. Past columns have discussed the comparison of Davids and Goliaths and the desire by many my-project-is-all-that-counts managers for the old Primavera P3 or SureTrak products. Two key needs – software that does what YOU need without a support team and administrator – and software to help push for the fastest delivery of the project. Despite the lost decade of the insignificant project in the portfolio of the enterprise, new software releases again support construction professionals.
Phoenix Project Manager 4 not only has the look and feel of P3 (modified oh so slightly perhaps for improvement or perhaps to avoid issues of copyright) but now finally (and after much nagging by this author) has the original choice of “best productivity” or “fastest finish” algorithms of P3. THIS IS A GAME CHANGER for those who learned at P3 and desire nothing else.
Other products that provide both a desktop (or laptop) MY-PROJECT-ONLY platform, including choice of users selected subdirectory storage, and choice of time-centric INTERRUPTIBLE or productivity-centric CONTINUOUS duration early start calculation include Oracle Primavera Risk Analysis PRA, previously marketed as Pertmaster,) and ASTA Powerproject.
Why is the choice of the INTERRUPTIBLE option so important? P3 supported the choice; P6 does not. Traditional CPM theory dictates the early start of an activity may be after the early finish of all of its successors. If the finish of the second activity is restrained by a finish-to-finish link, the original 1956 algorithm for earliest project completion will now show, for example, a ten day activity being stretched over 15 days. The superintendent (or perhaps even foreperson) will use discretion as to using a reduced crew, fewer hours, sending the crew for other tasks at appropriate junctures, all to pace the preceding activity driving the final effort of this activity.
This is important – we are not just moving bars on a screen. If progress on the preceding activity is not meeting expectations, we can choose to continue concurrent work or send the crew elsewhere to return when again needed. If progress is better than estimated, we can have our pacing crew speed up to capitalize on an early completion for both, perhaps to even finish the project early and earn a bonus.
If we are not concerned with earliest completion, or even with completion by a specified date, then we can use a different algorithm to attempt best productivity. This will purposely delay the early start of any activity that cannot finish until another activity is done so that the activity may be performed continuously. This is the algorithm for job shop scheduling, for getting those machines (or perhaps computer code developers) to work non-stop on one task, complete the task, move immediately to the next task, and provide maximum work for a set cost (machine rental or salary.)
The old P3 software product supported both options. To illustrate, see Figure 1 below. Task 001 is the first activity followed closely (and partially overlapped) by Task 002. The relationship is that 002 may start five days after the start of 001 but cannot finish until ten days after the finish of 001. Task 003 cannot start until five days after the start of 002. Task 004 requires finish of 002 and 003.
Figure 1 – Task 001 to 002 by SS5 and FF10, Task 002 to 003 by SS5, Task 002 to 004 by FS0, Task 003 to 004 by FS0
Using the continuous (job shop) mode, the start of 002 is pushed to day 10, rather than day 5, so that work may be performed continuously. However, this also means that the start of 003 is now pushed to day 15 rather than day 10 as perhaps initially intended. The entire project takes seven weeks. See Figure 2.
Figure 2 – Continuous Mode - Task 002 starts on day 10 not day 5, Task 003 starts on day 15 not day 10
Using the interruptible (fastest time) mode, the start of 002 is pushed to day 5 as intended, the ten day 002 is performed over fifteen days, the start of 003 is pushed to day 10 as intended, and the entire project can be completed in six weeks. See Figure 3.
Figure 3- Interruptible Mode – Task 002 starts on day 5, Task 003 starts on day 10, whole project requires six not seven weeks
The savings of one week comes at a cost – the crew working on Task 002 must either be paced over 15 not 10 days or must stop and remobilize to complete the work. P6 does not support the interruptible option. The work around is to split activity 002 into a 002A and 002B and replace the FF10 (finish-to-finish restraint with 10 days lag) to a FS0 (finish-to-start no lag) into 002B. This may require some additional effort both initially and with each update, but then the majority of users of P6 are either uninformed or may prefer the job shop scheduling mode.
Phoenix Project Manager 4 now also supports both modes, making it even more like P3 and better supporting the initial Primavera customer base of construction professionals most focused on timely completion. See Figure 4 for a comparison of Phoenix continuous and interruptible modes.
Figure 4 – Comparison of Phoenix Project Manager 4 Continuous and Interruptible calculation modes
ASTA Powerproject also supports the choice of continuous and interruptible options, but with a slight twist. The option is provided at the activity level rather than systemic. And when used, causing for example a 10 day activity to now be performed over 15 days, shows the duration to be 15 days. The 10 day duration is still in the database, unchecking the “interruptible” box brings back the original duration. See Figure 5 for a comparison of ASTA continuous and interruptible modes.
Figure 5 - Comparison of ASTA Powerproject Continuous and Interruptible calculation modes
While Oracle Primavera P6 does not support the interruptible option, their PRA (Primavera Risk Analysis, previously marketed as Pertmaster) does – again with a twist. PRA is the only product to select interruptible by default; their term for the option is STRETCHED. They also provide an option to interrupt only if the activity has an outgoing SS link (see 002 to 003 in our example) but will revert to continuous if this accommodation is not required. Of course, as noted above, the real benefit of interruptible is to provide the superintendent information on the earliest start even if this will require stretching or splitting performance. See Figure 6 for a comparison of PRA continuous and interruptible modes.
Figure 6 - Comparison of PRA Continuous and Interruptible calculation modes
Oracle has not yet provided an interruptible mode option for P6, but they appear to be hearing and responding to the needs of construction scheduling professionals. Many professionals not a part of a large “enterprise” organization (including outside consultants such as myself) have found the one-big-company and one-big-company-database model to be more difficult than the old all-on-my-laptop model of days of yore. While a single-machine architecture was supported, the Professional series’ use of a database designed for an enterprise, along with a dedicated Administrator and IT staff, has sometimes proved daunting. Oracle has heard us. The upcoming Oracle Primavera P6 version 8.4 for Professionals will now provide for a new and simpler database system. My sources say this will be Microsoft SQL Lite; there may be other options either with the new release or at a subsequent time. This change will make my life easier and I suspect the same for many other consultants, smaller companies, and even for larger companies which care to provide project superintendents with greater authority (and personal responsibility) untethered from a corporate IT department.
I suppose the release of this posting to my blog is timely – to celebrate Independence Day.
Fred,Just reading your column in Oct., 2015. Wow, I am happy to hear this. As a PM for over 30 years, who has an affinity for scheduling, I had given up on Primavera because...
Hi Fred,<br/>Another "integrative" software I have been very impressed with is Jean-Yves Moine's "CUBIX 360". <a href="http://3d-wbs.blogspot.com/" rel='nofollow'>http://3d-wbs.blogspo...
I was recently asked by a client to develop an equation to estimate the risk-related costs associated with implementing a recovery schedule. Using a ratio of the free floats for activit...
We love change orders as a drywall sub, just let us get our contract work done and pay us promptly on the change, not 6-9 months after we installed the work which often happens.