1. programacion inversa por fases

Steve Knapp*1, Roberto Charron*, Gregory Howell*
Phase planning today
Planificación por fases ahora
* Lean Project Consulting, Louisville, USA
Abstract
Since the publication of White Paper #7 “Phase Scheduling” (Ballard, 2000), work on many projects has been planned with this technique by teams of varying
configuration. Many teams have adapted their own approach to developing a “phase schedule”, in some cases called a “reverse phase schedule” or a “pull
phase schedule”. During these planning sessions, ideas have been put in practice that improve on the original scheme and increase the benefits of producing
a phase schedule. Perhaps the most significant being the conversations that the teams pursue during the exercise. This paper will briefly describe the authors’
current approach to and practices for preparing phase schedules and how this has become, in actuality, phase planning. It will then describe how phase
planning produces the project schedule as traditionally understood, and more importantly designs the network of commitments necessary to deliver each
project milestone, and how understanding and using the network of commitments improves project performance.
Keywords: Phase planning, scheduling
Resumen
Desde la publicación del artículo “Programación por Fases” (Ballard, 2000), el trabajo en muchos proyectos han sido planeado utilizando esta técnica con
equipos de configuración variable. Muchos equipos han adaptado su propio enfoque para desarrollar “programación por fases”, en algunos casos incluso
llamada “programación por fases inversa” o “programación por fases por arrastre”. Durante las sesiones de planificación, algunas ideas han sido puestas
en práctica que mejoran el esquema original e incrementan los beneficios programas por fases. Tal ves uno de los mayores beneficios son las conversaciones
que los equipos mantienen durante el ejercicio de programación. Este artículo describe brevemente el enfoque y prácticas de los autores para preparar
programación por fases y como esto ha llegado a ser, en realidad, planificación por fases. El artículo describe como la planificación por fases no solo produce
un programa de proyecto como se entiende tradicionalmente, sino además diseña una red de compromisos. Se explica como dicha red es necesaria para
obtener cada hito del proyecto y de cómo el entender y utilizarla mejora el desempeño del proyecto.
Palabras Clave: Planificación por fases, programación
White Paper #7 “Phase Scheduling” was issued
in April 2000 by the Lean Construction Institute (Ballard,
2000). It recommends the use of pull techniques and
team planning to develop a schedule for each project
phase. A phase is identified, usually with a start date,
finish date and very brief description (building skin,
excavation and slab on grade, preparation of construction
drawings, etc.) from the project master or milestone
schedule. The team, including representatives of each
organization working on the phase, gathers together in
a room. Each person then writes on a small piece of paper
(later to be stuck on the wall – thus “stickies”) their task
or the work that they will perform to release work to
another team member. These “stickies” are placed, on
the wall or a long piece of paper, moved around to reflect
the way the work will actually be performed, discussed,
adjusted, until finally a logic network is available.Typically
the team starts from the end of the phase and works
toward the beginning of the phase as they describe and
place their tasks on the wall thus adding only the work
that has to be done.
The team then adds durations to the tasks, again
discusses, moves the “stickies”, applies more or less
resources and determines the duration for the entire
phase. The White Paper stresses that these durations
Revista Ingeniería de Construcción Vol. 22 No
3, Diciembre de 2007 www.ing.puc.cl/ric 157
1 Autor de correspondencia / Corresponding autor:
Lean Project Consulting, 625 Main St. 1B, Louisville, CO 80027.
Phone 303-717-0952, E-mail address: sknapp@leanproject.com
PAG. 157 - 162
Best paper award
14th Annual Conference of the
International Group for Lean Construction
July 25-27 2006 - Santiago Chile

158
without the SOG however the phase chosen was too
large and complex for an initial session. The phase
plan, “the stickies” were converted to Microsoft Project
and used to manage the phase.
Case 2
Project: New wing on existing children’s hospital
Phase: Completion of excavation to basement SOG
poured
Participants: Architect, engineer, GC, relevant subs,
facilitator
Eureka moment: Many smaller moments. First planned
pour was completed nearly 4 weeks earlier than
originally scheduled before the meeting.
Discussion: The subs were already working together
on site.The session was led by the project superintendent
who allowed and encouraged deep discussion of the
issues.The resulting interaction between subs developed
a strategy for the phase and solved complex interlocking
problems between operating sewers, underground
utilities, structural integrity of the adjacent building
and limited site access. Pulling activities to produce
handoffs was new to participants who asked many
questions. The final stickies plan was converted to
Primavera SureTrack for actual use.
Case 3
Project: Installation of new Magnetic Resonance Imaging
(MRI) equipment in renovated MRI section of hospital
Phase: Entire project (only 3 months)
Participants: Architect, GC, relevant subs, facilitator
Eureka moment: none
Discussion: The architect’s description of the intent of
project helped everyone better understand the project.
The team planned for work to meet the milestones
previously established by GC PM on a CPM schedule.
These were used to focus discussion.
Case 4
Project: Heart Catheter Laboratory installation in
renovated hospital wing
Phase: From demolition complete to ready to install
lab equipment
Participants: Architect, owner, GC PM, all subs,
equipment supplier, facilitator
Eureka moment: The team initially discovered that they
would be unable to deliver the project when needed
by the hospital. Efforts to reduce the duration were
unsuccessful until the laboratory equipment supplier
offered to complete their work 5 days faster (out of 15)
should be the team members’ “best” estimate of the actual
time that will be spent, in other words without any
contingency time included. This duration will either meet
the requirements from the master schedule or not, the
team will make the necessary adjustments to arrive at a
practical end date and most importantly “publicly generate,
quantify and allocate schedule contingency (float)”.
According to the White Paper, this schedule, with its
publicly allocated float, has the “force of contract” and
can only be changed when the prime contract is changed,
the team agrees that they cannot meet the schedule or
finds a better, faster way to do the job. Development of
a phase schedule is an integral part of the application of
the Last Planner System to a project. In fact, the phase
schedule is the basis for a 6 Week Lookahead Plan and
ultimately the Weekly Work Plan, all essential components
of the Last Planner System® (LPS). In this paper the authors
will describe their experience with Phase Scheduling, in
particular how they see it as being more than just a means
of preparing a better and more effective Gantt chart type
schedule for a project.
2. Experience and development
The authors have participated in dozens of phase
scheduling sessions. Contrary to the White Paper, none
of these have ended with a contractually binding schedule;
instead, virtually all of them have provided something
more valuable – a team that understands their project,
their individual roles and what is required for success on
the project. Here are a number of actual but disguised
examples of how phase scheduling sessions have worked.
Case 1
Project: Cancer Center
Phase: From opening ground to steel erection
Participants: General Contractor (GC), relevant subs,
chief nurse, architect, engineer, owner project manager
(PM), facilitator
Eureka moment: Erect steel prior to placing and curing
slab on grade (SOG) – saved 6 weeks of construction
time
Discussion: The subs had not worked together before
but the GC and Owner had. A senior nurse and architect
began the meeting with a much-appreciated explanation
of the value to be delivered by the project. This was
followed by a simple demonstration of phase planning
on a very small piece of the project. The session was
facilitated by the GC PM. As the phase plan developed,
it became obvious that the steel could be erected
3, Diciembre de 2007 www.ing.puc.cl/ric
Steve Knapp, Roberto Charron, Gregory Howell

159
process. The facilitator needs to keep the meeting
on track and must not push forward their solutions.
•The size and length of phase selected is very important
– too large and complex, with too many players
makes the session much less effective – a typical
session should be completed in less than 4 hours.
Good advice for selecting the first phase is to cut
what appears to be reasonable in half.
• It is very important that the session participants come
properly prepared and have enough information,
experience and authority to make “deals” regarding
their performance on the project. See the meeting
invitation in the Appendix for an example of the
suggested pre-work.
• “Pulling” tasks is probably the hardest for people to
understand and accept. The facilitator is frequently
questioned and challenged about this. It is an ongoing
battle to keep people working from the end of the
schedule to the beginning – people just want to plan
as they are accustomed. Reverse planning is easier
when a clear strategy for the work in the phase has
been established.
• The level of detail (size and number of tasks) that
will be represented on the wall is always an issue –
typically it is not a problem as the level of detail is
established by the team. They seem to understand
what level is necessary to describe their work, both
for their own use and so that others grasp the
requirements for handoffs.
• Establishing the context helps. An introduction to
the project by either the owner or architect makes
a difference to the players – seldom do they really
know how the client defines “value” on the project.
In an unmentioned case, the owner, a developer,
explained the financial implications of the project
cost and timing to the subcontractors. These
implications were much discussed during the day
and shaped a variety of choices made by the team.
• There is no simple nor accurate way of immediately
determining the overall duration of the phase from
the “task durations” that have been added to the
“stickies”. It is very hard to understand the impact
of overlapping tasks, those that start prior to the
completion of another task. In most cases, overlaps
should be avoided by breaking the first task into
subtasks that release work to the following team in
established increments. Establish that the durations
are in work days, not calendar days. The conversion
of the “stickies on the wall” to a usable schedule for
a project is essential and often quite difficult to
if the equipment installation could begin in time to
complete by year-end. This increased value for both
the hospital and the installation contractor.
Discussion: The session was run by the superintendent.
The subs knew each other well and had previously
installed a similar laboratory in the same hospital a
year earlier. They reflected on that experience to refine
the approach with effective collaborative interaction
The stickies were converted to MS Project for actual
use.
Case 5
Project: New wing on Childrens’ hospital
Phase: Preparation and Issuing of Construction
Documents
Participants: Architect, engineers, GC, facilitator
Eureka moment: Smaller breakthrough lead to a
significant improvement in scheduling of the reviews.
Discussion: New format for “stickies” on wall that
included the use of a preprinted calendar on the wall,
modification of “suits and boots” (designers and field
staff) review procedures, the plan was accepted by all
participants.
Case 6
Project: Medical Office Building
Phase: Ground breaking until slab on grade
Participants: Architect, owner, GC, relevant subs,
facilitator
Eureka moment: The explanation of site limitations by
the excavator.
Discussion: Subs were entirely new to each other –
good portion of session was devoted to “building trust
and understanding” what each needed for project
success. The team had a difficult time building a phase
plan until the excavation contractor explained how site
limitations dictated the initial strategy. This clarified the
situation so that the phase plan was produced quickly.
The stickies converted to SureTrack for actual use.
Lessons learned from these cases:
These cases demonstrate many different ways
the original White Paper instructions and theory have
been interpreted and applied. Several lessons were
apparent from these sessions. More theoretical
considerations will be discussed later in the paper.
• There is no single person or staff role best suited to
run the session – it depends on team chemistry and
who knows the most about what work needs to be
done in the selected phase or can best manage the

160
accomplish. Typically work by the project manager
and scheduler after the meeting is required – in the
best cases, accurately reflecting the work of the team,
in not so good cases, reflecting the prejudices of the
project manager. In any case, the team should not
leave until they are confident that they can deliver
the work in the time required.
• The White Paper states that as the “stickies” are being
placed on the wall, “planning breaks out”. This is
very true and the single most valuable part of the
session. Discussion about how the work will be
performed and what is required to begin or
accomplish each task is very important. The better
this information is reflected on the “stickies” the
better the results of the session.
Figure 1. Stickies on the wall with planning occurring
• A facilitator in a phase planning session typically
answers the “Why are we starting at the end?”
questions but also stresses the need to define handoffs
between team members. A facilitator can be most
effective by working with the team members to assure
they really have defined the start and end of their
tasks and have received or given a promise as to
what will be in place at the moment of handoff.
• The usual comment from participants in a phase
scheduling session is “We have never done this before
– we are always given a schedule and asked to
comment on it – never given the opportunity to
develop one ourselves. This seems good.”
With this understanding of how typical phase
planning sessions are conducted, we can look at what
the authors see as the most important outcomes of these
sessions and then what more might come from a session.
Benefits of phase scheduling as currently practiced:
• Project team gain a better understanding of project
value.
•Team has opportunity to meet and become comfortable
with others on the team as they plan the work.
• Each member knows what others on the team need
to accomplish their tasks, what is important to the
success of others.
• The work is planned so that all understand and agree
on what is to be done and about when. The team
knows how to prepare to make the promises needed
to execute the work according to this plan.
• A logical sequence is planned for the work and
reasonable durations attached to the activities.
• Gantt charts created from the team’s schedule are
believable.
• The team knows where the source of the 6 Week
Lookahead Plan used to make work ready during the
remainder of the phase and project.
3. Phase planning and a network of
commitments
When the White Paper stated that “planning
breaks out” what did it mean? First, the participants in
the planning session understand value of the project was
and were thinking about the best way to achieve it with
minimum waste.
Starting at the end of the phase (SOG poured,
Construction Drawings issued) and working back to explain
what it took to get there does three things: 1) What they
will turn over when their task was completed is identified,
2) Their task has been explained to others and later how
long it will take established, and 3) They have defined
what they need to accomplish their task.
The participants not only defined their task –
they identified and described “hand offs” both to and
from their work. The easy part of phase scheduling is to
define and represent the individual tasks – everyone does
it and is used to seeing the task represented on a Gantt
chart as a line with a beginning and an end indicating

161
as the add and discuss the tasks and “hand-offs” shown
on the wall. This is very different from the typical schedule
development where a prepared Gantt chart is provided
to the team and they are asked to “comment” on it and
very shortly asked to accept it as part of their contract.
Once a network of commitments, personally
developed and accepted by each member of the team is
available, project management becomes an effort to see
that the network is activated, that the work is made ready
to people can make an explicit promise for it to be
completed on a specific day. This happens when the team
uses a 6 Week Lookahead Plan (6W LAP) to make their
work ready. The 6W LAP shows the coming six weeks of
activities as they were placed on the phase schedule.
There are several ways of preparing a 6W LAP from the
phase schedule ranging from simply transferring the
activities to an Excel spreadsheet (sample below) or, if
the phase schedule has been converted to an MS Project
or SureTrack format, using the built-in software filters to
show just the next six weeks’ activities.
the start and finish times. Sometimes there is a predecessor
and successor activity that identifies what must be done
before and after the actual activity.
The difference in phase planning is that the
participants discuss these “hand-offs” (and the predecessor
and successor activities), understand the impact and
negotiate the best way of achieving them. Some phase
planning sessions have represented the “hand-offs”
(“needs” and “releases”) on the “stickies” that are pasted
on the wall (see Figure 1) Other sessions simply make
sure that the participants understand and accept the
“hand-offs” as a necessity for success. In most cases the
discussions have resulted in improved or changed ways
of performing the work and thus better project
performance.
This discussion of “hand-offs” and the
acceptance of them by each participant, establishes the
basis for a commitment from one performer to another.
The team designs the network of commitments, the
requests and promises, necessary to complete the work
Figure 2. Sample preprinted “stickie”
Figure 3. Sample Excel spreadsheet used to represent work for next six weeks

162
The 6W LAP serves as a basis for a project
meeting where the appropriate leaders examine each of
the activities planned for the next six weeks and ask “Are
there any reasons why these activities cannot be completed
as scheduled?” In other words, can the planned
commitments be kept? When the answer is “no”, it is
considered a constraint and listed with a “promise date”
when the relevant person commits to have it removed or
to remove it on their own. In this way the network of
commitments, first designed in the phase planning session,
are continuously monitored and made the focus of project
planning.
It is beyond the scope of this paper, but the next
step in the Last Planner System involves a similar process
where the actual task performers make commitments, not
only as to what task they will do, but on what day they
will complete it. The successful completion of these
commitments is recorded and tracked as Plan Percent
Complete – again monitoring the network of commitments
that serve as the basis of project success.
4. Phase planning and value stream
mapping
The authors have worked with several projects
and organizations interested in applying the concept of
Value Stream Mapping (VSM) to their operations. A
detailed discussion of VSM is beyond the scope of this
paper but a brief description of how it works will help
the reader understand why the authors feel that the same
concepts of planning are involved in both.
VSM is typically used in a manufacturing
environment where product is produced by a number of
machines or fabrication operations.The flow of the product
is determined by the location of the machines and the
way the product is moved between them. VSM maps this
flow and determines the actual time work is done on the
product and time that the product is being moved or is
waiting, in other words waste. When the waste is identified,
a future state map is prepared that eliminates as much of
the waste as possible and the team looks at ways to
achieve these improvements. Additional parts of the map
indicate how information flows to the machines (or their
operators) to determine the rate of flow.
One of the interesting differences between the
manufacturing world and the construction world is that
in manufacturing the product flow is determined by the
physical location of the machines, in construction the
product flow is determined by crew level assignments.
The craftsmen are assigned what work will be done when
and told to work in different areas at different times in
accordance with some plan. On typical jobs this plan is
a CPM schedule. As we have seen above, on a project
managed with the Last Planner System this plan is
developed by the staff actually doing the work. This phase
plan can be seen as a value stream map demonstrating
the flow of work from one activity to another, though
related more by time than physical location. The addition
of task durations and the allocation of float is similar to
the VSM approach of determining cycle time and overall
time at a work station. Similar discussions take place as
a team develops a phase plan or works out the detail of
a VSM.
Both phase planning and VSM rely on the
concept of pull to provide a map or plan that does only
the necessary work to accomplish the goals. By doing
this, much of the unnecessary additional effort (waste) is
eliminated.
5. Conclusions
The authors started working with teams to
implement “phase scheduling” as described in White
Paper #7, as our work progressed we realized that the
effort was accomplishing much more than “scheduling”
– it had become “planning”. Not only planning by the
project planner and project leaders but by the team that
would actually do the work. We believe that this is a
critical step forward in understanding how projects can
be completed more successfully.
6. Acknowledgements
The authors have worked with a number of
different organizations and project teams while assisting
in conducting phase planning sessions – in all of those
sessions the participants have acted in a helpful and
learning manner. We thank all of them for demonstrating
to themselves and to us that phase planning really brings
a new dimension to project planning.
7. References
Ballard G. (2000), “Phase Scheduling” LCI White Paper
#7 Lean Construction Institute, Berkeley, CA.
Rother, Mike and Shook, John. (2003), Learning to See
– Value-Stream Mapping to Create Value and Eliminate
Muda. The Lean Enterprise Institute, Brookline, Mass.

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