Short presentation that tries to explain what As Late as Possible constraint is and what it does. I hope to clarify some of the misconceptions surrounding its use. Please send your feedback if the information provided was useful.
Uneak White's Personal Brand Exploration Presentation
113015 - Understanding ALAP
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Prepared by : RUFRAN C. FRAGO, P. Eng., PMP, CCP, PMI-RMP, Author
Revision 1 : November 30, 2015
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ANNOUNCEMENT!
More learning related to the subject can be found in the book "Risk-based Management in the
World of Threats and Opportunities: A Project Controls Perspective." It is now available in
paperback and Kindle edition at Amazon.com. Follow the hyperlinks below for more information.
http://www.amazon.com/RUFRAN-C.-FRAGO-PMI-RMP/e/B01055MPYI
http://www.amazon.com/dp/B0104OFUDI/ref=rdr_kindle_ext_tmb
https://www.amazon.com/author/rufrancfrago
The book provides new/additional knowledge to project management practitioners (beginners to
experts), risk management specialists, project controls people, estimators, cost managers,
planners and schedulers, and for students of undergraduate courses in Risk Management.
The sectional contents offer practical and common sense approach to identifying/managing
risks. It is a must have for company managers, directors, supervisors, aspiring industry
professionals, and even those students fresh from high school. The material is especially design
to start with the foundational principles of risk gradually bringing the reader to deeper topics
using a conversational style with simple terminologies. You can grab a copy now.
https://youtu.be/wxWgYUhiWos
Source:
Frago, R., 2015.Risk-based Management in the World of Threats and Opportunities: A Project
Controls Perspective
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TABLE OF CONTENTS
Effects of ALAP, Example No. 1 - Page 4
Effects of ALAP, Example No. 2 - Page 5/6
Effects of ALAP, Example No. 3 - Page 7
ALAP, What is it all about? - Page 8/10
Known Possible Benefits of ALAP - Page 11
Known Possible Drawback of ALAP - Page 12/14
Guidelines to Using ALAP - Page 15
References - Page 16
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RESULTS:
1) The whole schedule becomes critical. The float was sucked out. The schedule is now an As Late
as Possible Schedule, looking at the late dates as target.
2) The ALAP blanket assignments changed the dates of the activities belonging to the critical path.
Example No. 2, continuation…
Same schedule showing Longest Path with Blanket Application of ALAP
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Same schedule showing Longest Path with Selective ALAP (from RFFC, RAS, to CON)
Example No. 3
8. • Tasks are scheduled as-late-as-possible (ALAP) based upon the
target end date
• In a well crafted schedule and you can’t start activities earlier
than their early start and you can’t finish later than their late finish
without affecting the critical path. Actual times should fall into this
envelope.
• The contractors want to finish non-critical activities as early as
possible so they get paid sooner and so delay doesn’t get
blamed on them. The owner wants them to finish non-critical
activities as late as possible to lessen the risk of change (it costs
lot less to move a footing before it is placed).
• Usually intuitive resource leveling dictates the contractors spread
out the non-critical activities anyway. For these reasons it is
recommended to give the contractors as much access to float as
possible but also that they schedule non-critical activities at the
“last responsible moment” (1).
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As Late as Possible Scheduling, what is it all about?
9. • As Late as Possible constraints at this time does not affect the
calculation of the Quantitative Risk Assessment but affects and
works against CPM in the regular scheduling work environment
as Primavera or MSP. ALAP should be avoided or used
selectively and intelligently as they can create artificial critical
path.
• ALAP is also known as activities with Zero free float. Further
discussion is widely available in the net between ZFF and ALAP.
• CAUTION: The constrained activities are being delayed using As
Late As Possible without delaying any succeeding activities. This
is risky, as any delay in delivery will then delay work activities.
Special concern is for Owner-supplied material. Verify the
reasonableness of all durations above.
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ALAP, what is it really?... (Continuation)
10. • NOTE that it is the Contractors who usually like to delay material
delivery (1) to reduce storage costs and (2) because a down
payment is required and contractors like to delay spending any
money as long as possible.
• Where an activity would otherwise be scheduled as late as
possible, the introduction of a contingency period buffering its
end date will have the effect of scheduling the planned
commencement of the activity earlier than would otherwise be
the case. The effect of this will provide for a degree of delay in
the completion of the activity to be absorbed by the contingency
period (2).
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ALAP, what is it really?... (Continuation)
11. • Using a production analogy, work-in-progress (WIP) are minimized
and not incurring costs earlier than necessary.
• From the project manager’s viewpoint, there is better focus at the
critical start of the project because there simply aren’t as many
tasks scheduled to start.
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Known Possible Benefits of ALAP
12. 1. As all tasks are critical once you are in tracking mode. An increase in
duration of any task will push out the project end date by the increased
amount
2. Student Syndrome (3)
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Known Possible Drawbacks of ALAP
13. 3. Scheduling with “As Late As Possible" dates means that the schedule
will have an increased probability of not being able (if not impossible to
achieve) since there is no more room for anything being late. A very
risky thing to do. Instead, define a "deadline" date for the completion
milestones and schedule and let Primavera compute when it will get
done, and if the PC Team don't like the date it computes, then they
have to change the plan.
4. In Primavera, ALAP absorbs only the float (free float) but was not
known to affect successor activities. However, in MSP, it does. It sucks
the free float and the total float as well, delaying the successor activities
in the process. (4)
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Known Possible Drawbacks … (Continuation)
14. 1) Avoid using blanket application of ALAP. It is a scheduling constraint
that is rarely used except on special situation. As such, it should be
used wisely and intelligently (fit for purpose).
2) Evaluate your target objective first before employing ALAP. Always
remember that ALAP sucks the float out from the path. It can change
the existing critical path/s and can introduce new challenges to existing
strategies.
3) Ensure that the project’s objective is specific before applying ALAP.
Otherwise, a too general application of ALAP will result to what the
project never really intended.
4) ALAP scheduling for convenience will not benefit the project in the end.
5) What comes after ALAP is usually activity delay as the float is no longer
available to play with.
6) Excessive use of ALAP is not a good scheduling practice. It sets the
projects up for failure.
7) ALAP can result in difficult court claims for the one who is using it.
8) Contractors love to use ALAP when submitting their Baseline Schedule
but use their Optimistic schedule when executing.
9) As much as possible, use ALAP only on non-resource loaded activities
such as waiting time, delivery time, documents preparation, and the
like. Limit using ALAP on activities requiring direct resources.
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Guidelines to remember before assigning ALAP Constraints
15. 10) Avoid combining FF and ALAP whenever possible. The project needs
to review the reasonableness of existing FF relationships in the
schedule. This is a bad combination.
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Guidelines to remember before assigning ALAP Constraints
16. 1. Frago, R., 2015.Risk-based Management in the World of Threats and Opportunities: A Project
Controls Perspective
2. AACEi Forum on Early dates and Late dates (Bill McManus-28Oct09)
3. AACEi Forum on Schedule Contingency Management (Keith Pickavance - 26Nov09)
4. 2012, www.spspro.com
5. 2013, Paul Harris, Project Planning and Control Using Primavera P6, Page 11-2
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REFERENCES