Pergamon International Journalof Project ManagementVol. 16, No. 4, pp. 215-221, 1998
© 1998 ElsevierScienceLtd and IPMA. All rights reserved
Printed in Great Britain
0263-7863/98 $19.00 + 0.00
Construction process improvement
methodology for construction
Alfredo Serpell* and Luis Fernando Alarc6n
Department of Construction Engineering and Management, School of Engineering, Pontificia Universidad
Cat6lica de Chile, Casilla 306, Correo 22, Santiago, Chile
A methodology developed for construction improvement and waste reduction is presented. This
methodology has been successfully applied during the last 3 years to several construction sites in
Chile, through consulting services and research studies. The approach includes a set of structured
activities and tools that are performed and applied for the identification and evaluation of the
problems that produce construction waste, and the causes associated to them. A second stage of
the approach corresponds to the development of both short and mid-term solutions in order to
act on the factors that produce these problems with the purpose of reducing or eliminating their
effects. A summary of the major improvements achieved through the application of this framework is also included to show the potential of this approach, specially in countries where the
construction industry is characterized by the low educational level of its workers and the many
technological limitations that still pervade some construction sectors, particularly the housing
construction sector. © 1998 Elsevier Science Ltd and IPMA. All rights reserved
Keywords: construction improvement,waste reduction, construction management, methodology,applied research
An increasing number of construction companies are
applying actions to improve their projects’ performance by reducing all kinds of waste during the construction process. This trend has been progressively
increasing during the last 3 years offering many consulting and research opportunities to the authors of
this paper. During this time, an structured methodology for improvement has been developed and
applied with increasing success to several construction
projects in Chile, particularly in the housing construction sector due to its technological limitations and the
fact that most of its workers have a very low educational level when compared with other sectors like
industrial or mining construction. This approach is the
focus of this work and it is described in the following
A general methodology for improvement of the
To ensure the effectiveness of improvement activities it
is necessary to use an structured yet flexible methodology that serves as a guideline for these efforts. This
structured approach has been generated from experi-
*Author for correspondence.
ence obtained during the execution of several types of
improvement activities in many construction sites
during the last 6 years. All of these efforts have been
directed to construction performance improvement
through the reduction of waste and the elimination of
Underlying concepts and background
Waste has been defined by Alarctn ~ as “anything
different from the absolute minimum amount of
resources of materials, equipment, and manpower
necessary to add value to the product”. In general, all
construction activities that produce cost, direct or
indirect, but do not add value or progress to the product can be called waste. Then, any improvement
effort should be focused on identifying waste in the
construction process, analysing the causes that produce
this waste, and acting over these causes to reduce or
The methodology for improvement is based on the
construction process model described in Figure 1z.
According to this figure, there are three areas or elements of interest where waste can occur and improvements can be carried out:
1. Flows, both internal and external which are the
inputs to the conversion activities and can be classi-
Construction process improvement methodology for construction proiects. A Serpell and L F Alarc6n
Figure 1 Construction process model
fled into two groups: construction resources (materials, labour and equipment); and construction information.
2. Conversion processes and resultant products, which
are the processes that transform the flows into completed and partially completed products.
3. Flows and process management which corresponds
to the management actions and decisions that determine the way things are done and the application
of construction resources. This management is responsible for the performance of the construction
process and is characterized by different styles or
approaches according to companies and managers.
Problem solving methodology
The general approach utilized for performance
improvement was adapted from traditional problem
solving methodology. General problem solving
addresses a situation where what is happening is less
than desirable, with the aim of rectifying the situation 3.
In this case, the methodology is generally applied to
an ongoing construction project that is studied for
improvement. Figure 2 displays a flow diagram of the
main steps included in the methodology.
As shown in the figure, the methodology has several
loops to correct problems that can arise during the
improvement process due to the characteristics of the
particular situation (management style, labour characteristics, performance requirements, etc.). Also, after
its repeated application, the methodology provides several lessons learned, that become an important source
of information for future improvement processes. This
is a very important feature of this structured
Diagnostic of current situation. The first step of the
methodology starts with the observation, data gathering, and data processing of the construction process,
that is, resources and information flows, conversion activities and management of flows and conversion processes. The aim is to obtain the most complete and
accurate picture of what is happening in the project.
Several activities are carried out based on the application of many tools during this stage. The most common and effective are as follows:
1. Work sampling: to obtain information about labour
2. Waste identification survey: to obtain people’s perceptions about types of waste that are occurring in
the site and identification of their possible causes ~.
An example of some of the results obtained from
the application of this survey is shown in Figure 3.
3. Foremen delay survey: to identify causes of delays4.
4. Processes observation and representation: to obtain
information about construction methods, resources
Review new identified I
areas or improve
|~[||Diagnostic of current situation|
|Analysis and Identification of|
actions are not
does not work
Desire/need of Waste Reduction
Definition and Evaluation of Improvement
Strategies and Actions
Monitoring and Evaluation of Obtained Results [
Corrective ActionSto Assureand MaintenanCeBenefits of Changes I
Planningof Implemonta on …………………………………….. I xporionco andiknow,edgo 1
and Implementation i
Figure 2 Construction process improvement methodology
Construction process improvement methodologyfor constructionprojects. A Serpell and L F Alarc6n
L, l 0
Causes d ~ t e
Figure 3 Example of results obtained from waste surveys
utilization, processes performance and safety, etc.
The idea is to mapping out the process to understand it in detail and to identify potential problem
5. Site layout and temporary facilities study: to obtain
information for studying the adequacy of the site
layout and site facilities.
6. Organization and management study: to evaluate the
management and organization effectiveness, considering the main functions like planning, direction,
quality management, etc.
7. Labour work satisfaction study: to evaluate work climate on site.
8. Study of material acquisition and handling systems:
to evaluate their effectiveness and the performance
of external and internal suppliers.
9. Study of construction equipment utilization: to check
utilization rates, activity levels for each equipment,
10. Clients’ satisfaction survey: to obtain information
of the satisfaction level of clients and to evaluate
the value given by them to different product and
11. Quality survey: to obtain information of the
most recurrent quality failures and problems, as
well as the cost of repairing or correcting them.
Figure 4 shows an example of some of the results
obtained from a construction site.
After all the necessary information has been gathered, this is reviewed with the aim of achieving the following objectives:
• Obtain a clear and comprehensive understanding of
every aspect related to the project construction process under study.
• Identification of waste, including non-value-adding
• Identification of management and organizational deficiencies.
• Identifying possible causes of waste and deficiencies
and selecting the most important ones.
• Identifying immediate (and sometimes obvious)
improvement opportunities easy to implement.
If necessary, additional data gathering activities are
performed to verify unclear information or detected
causes that are not totally proved.
Analysis and identification of improvemen t opportunities.
Once the identification of waste and its causes has
been accomplished, the next step is to find out cost
effective improvement opportunities that can be
applied to reduce waste or to improve productivity.
This analysis is performed using teamwork and brainstorming among the members of the team. The information is presented to the team and each member
provides ideas and recommendations of potential
improvements that can be applied to the construction
process. Experience plays a crucial role in this stage.
The final result of this stage is a list of selected
improvement opportunities, arranged according to
their perceived benefit.
Definition and evaluation of improvement strategies and
actions. After selecting the most promising improvement opportunities, a set of improvement strategies
and actions is identified for each one, again using
teamwork. An initial selection is performed to reduce
the number of alternative solutions. Each selected
improvement strategy and action is evaluated in terms
of: technical feasibility; economic feasibility; time feasibility; cost of implementation; and associated benefits
Construction process improvement methodologyfor constructionprojects: A Serpell and L F Alarc6n
Causes of quality problems
Figure 4 Example of quality survey results
of its implementation. As a result of this evaluation,
the feasible and most profitable strategies and actions
are selected for implementation. Also, a goal is set and
a performance measurement is selected for each one to
be used during and after implementation, to check if
the desired level of improvement is actually achieved.
Improvement strategies and actions defined at this
stage can be classified according to the following criteria:
• Timing of implementation: short-term or mid-term
• Scope of improvement: corrective actions and/or
changes of the current construction process
approach. In the first case the aim is to correct deficiencies and problems that are present in the current construction process (examples: improving
planning; training workers to improve the work they
are doing; reducing transportation distances; reducing crew sizes; etc.), while in the second case the
idea is to change the way in which the construction
process is carried out (examples: implementing a
different construction method or technique; restructuring the site organization; etc.).
Planning of implementation and implementation. The
most difficult step of the improvement methodology is
the implementation of improvement strategies and
actions. According to authors’ experience, the most
important factor of the implementation plan is to consider the way that resistance barriers of the personnel
will be overcame. Then it is critical to ensure that implementation is understood and accepted by all the
people that will be affected by changes. Some of the
typical activities considered in an implementation plan
• Obtaining real commitment from management.
• Communicating the plan to personnel in the most
convenient way and with an emphasis in reducing
• Training people on the changes to be made.
• Supporting people during implementation.
• Changing documentation.
• Analysing potential impacts of changes on other
construction areas or processes.
Monitoring and evaluation of obtained results. This
stage is used to determine the results obtained from
implementation, using selected performance measures
for each improvement action. The focus at this stage is
to review the actual improvements achieved by implementation, the difficulties faced during implementation, and the reasons that precluded improvement or
reduced the expected gains. Decisions should be made
at this stage based on the results obtained and the
analysis of the implementation process. Some of these
decisions are to apply corrective actions to the implementation process, to loop back to a previous stage
to review the improvement methodology, to stop the
improvement process due to its failure, or to wrap up
a successful implementation by adopting best practices
and other learned lessons.
Corrective actions and maintenance of changes to assure
benefits. According to results obtained in the previous
stage, corrective actions considered necessary to make
the implementation more effective are adopted in this
stage. A second aim of this stage is to assure the maintenance of the implemented changes, to assure the
short and long-term benefits expected from them. This
aspect is critical in the Chilean construction industry
due to the low educational level of the majority of the
workers and to the fact that most of them learnt their
trade from practice. Then, there is a strong tendency
to return to their traditional construction methods
when time passes by if no follow-up measures are
taken. This is true even in the case that the improved
methods are easier or require less physical effort5.
Figure 5 is an attempt to summarise the methodology and the different activities performed in each
step as described above.
The methodology of improvement just described
represents a systematic attempt to organize the implementation of performance improvement processes
in construction projects. However, this methodology
should be flexible and adaptable to the specific needs
of each construction project situation. To obtain effective results and successful implementation it is also
necessary to develop a synergistic relationship with
management and supervisory personnel of the construction project.
According to the authors’ experience, working in a
team approach with the project team is a requirement
to obtain good results. If this condition is not
achieved, the improvement process is continuously hindered by lack of trust, bad attitudes, lack of commitment and other negative situations.
Construction process improvement methodology for construction prt~/ects. A Serpell and L F Alarctn
Definition and [
• Causes of failure
• Identificationof corrective actions
|• Performance data gathering tools|
• Construction waste identification
• Study of construction processes
• Study ofjob-site organisation
• Project organisation and
• Study of resources procurement
• Study of quality and quality system
• Study of equipmentutilisation
• Technical feasibility
• Time feasibility
• Cost of implementation
• Benefits of implementation
• Obtaining management
• Communicating plan to personnel
• Training people
• Supporting people during
• Changing documentation
• Analyse lateral impacts
• Define performance measurements
• Measure results
• Decisions about improvement
• Gatheringof lessons learned
• Implementcorrective actions
• Maintaineffective changes
• Work sampling
• Foremen delay survey
• Waste identificationsurvey
• Statistical data analysis
• Construction processes analysis
• Crew balance charts
• Procurement, storage, and resources
• Labour satisfactionsurvey
• Equipment utilisation sampling
•Teamwork and brainstorming
• Cost estimating
• Planning tools
• Short-term planning tools
• Documentation systems
• Performance measurement
• Statistical data analysis
• Cost measurements
• Construction processes analysis
• Training activities
• Planning tools
Figure 5 Summary of the improvement methodology (adapted from Ghio et al. 5)
The application of this m e t h o d o l o g y can be extensive and detailed, or limited and global depending on
the goals defined for the i m p r o v e m e n t process and the
characteristics o f the construction process. In our experience in four housing projects with construction
rates of 150-300 houses a year we have spent 2 –
3 months for the diagnostic stage and a r o u n d a year
when implementation and follow-up o f some m a j o r
i m p r o v e m e n t actions were included. In fact, the goal
should be to prepare the project personnel to sustain a
continuous improvement process considering the multiple possibilities of i m p r o v e m e n t that can be found in
I m p r o v e m e n t a c t i o n s
As explained before, i m p r o v e m e n t actions or reco m m e n d a t i o n s can be classified according to the timing and d u r a t i o n of their implementation and to the
scope of improvement.
Short-term improvement actions take advantage of
improvement opportunities which can be achieved
easily with a low effort and low economic investment.
These improvement actions require the involvement of
few people and a short time for implementation (1
3 months). Some of them can be implemented almost
immediately, for example, providing a mobile site materials and tools storage system or establishing adequate t r a n s p o r t a t i o n routes to reduce transportation
and travelling time.
Short-term actions can provide important improvement benefits to construction projects. Most of the
construction projects in Chile offer many of these
opportunities due to technological limitations and lack
of a construction engineering function on site, specially
in the housing construction sector. Generally most of
these short-term actions are limited to minor changes
to correct the way in which things are currently performed.
Mid-term recommendations require more analysis,
planning and design for their actual implementation.
Typically these actions require deeper changes and the
benefits of introducing these changes are usually not
obvious 5. In most of the cases these actions require a
significant development effort, a longer implementation
time, and their scope includes the use of innovative
construction methods, new planning and control strategies, new technology, new m a n a g e m e n t systems, etc.
Mid-term actions may require considerable initial
investments and consequently, should be well evaluated and well planned before implementing them to
assure the effectiveness o f the changes.
Construction process improvement methodology.for construction projects: A Serpell and L F Alarc6n
Table 1 Summary of selected improvement actions
Construction projects Improvement opportunities Improvement actions
project with a total
of 324 units
project with a total
of 30 units
project with a total
of 2000 units
• Inefficient use of manpower
• Poor operational planning
• Lack and low quality of resources
• Lack of management support systems
• Inefficiencies in construction methods (concrete
work, masonry work)
• Quality problems
• Complaints by clients regarding repairing service
• Waiting time due to lack of equipment and interference
• Inefficient use of manpower
• Inefficiencies in construction methods (formwork,
• Excessive transportation time
• Overmanning of crews
• Inefficient use of manpower
• High level of reworking time
• Poor operational planning
• Inadequate construction method
• Reduction of waiting time by improving materials
• Implementation of an effective short-term planning
• Improvement of construction methods and reduction
of construction crews
• Implementation of a quality assurance system
• Reduction of service cycle time by increasing response capacity
• Implementation of last planner concepts in a microplanning system
• Reduction of construction crew sizes
• Provision of more efficient tools for formworking
• Use of light-weight concrete and pre-fabrication for
some concrete elements
• Improvement of site layout and reduction of transportation time making resources more accessible to
• Reduction of personnel in excess
• Balance crews and improvement of operational planning
• Training of personnel
• Implementation of operational planning system
• Change of construction method by changing
masonry-based structure to a concrete structure
A s u m m a r y o f s o m e i m p r o v e m e n t a c t i o n s w h i c h
h a v e b e e n r e c e n t l y a p p l i e d o r s u g g e s t e d to t h r e e
e x t e n d e d h o u s i n g c o n s t r u c t i o n p r o j e c t s is s h o w n in this
s e c t i o n as a n e x a m p l e . Table 1 s u m m a r i s e s t h e s e
a c t i o n s .
O b t a i n e d r e s u l t s
M a n y s i g n i f i c a n t results h a v e b e e n o b t a i n e d f r o m the
a p p l i c a t i o n o f this i m p r o v e m e n t m e t h o d o l o g y to several c o n s t r u c t i o n projects. T h e m o s t i m p o r t a n t results
are d e s c r i b e d in the f o l l o w i n g sections.
Table 2 s h o w s a s u m m a r y o f selected d i r e c t a n d
e x p e c t e d benefits o b t a i n e d f r o m the s a m e p r o j e c t s c o n –
sidered a b o v e .
T h e a p p l i c a t i o n o f the s t r u c t u r e d i m p r o v e m e n t m e t h –
o d o l o g y p r o v i d e s a d d i t i o n a l benefits b o t h to the c o n –
s t r u c t i o n c o m p a n y a n d site a n d to the r e s e a r c h e r s .
First, a f t e r the initial fear t h a t i m p r o v e m e n t a c t i o n s
p r o d u c e s in the p e o p l e , the i n v o l v e m e n t o f the c o n –
s t r u c t i o n p e r s o n n e l in i m p r o v e m e n t activities s t i m u –
lates t e a m w o r k a n d facilitates c o n t i n u o u s
i m p r o v e m e n t . C o n s t r u c t i o n w o r k e r s a n d s u p e r v i s o r s
b e c o m e m o r e c o n s c i o u s a b o u t t h e i r c o n t r i b u t i o n to the
g e n e r a l p e r f o r m a n c e o f the p r o j e c t , s u p p l y i n g n e w
ideas a n d r e c o m m e n d a t i o n s .
S e c o n d , m a n a g e m e n t b e c o m e s m o r e a w a r e o f the
i m p o r t a n c e o f its role w i t h r e g a r d s to the feasibility
a n d effectiveness o f the i m p r o v e m e n t process. T h e y realise t h a t t h e y s h o u l d b e c o m e the c h a m p i o n s o f the
p r o c e s s b e c a u s e in this way the rest o f the p e o p l e
d e v e l o p t r u s t a n d c o m m i t m e n t o n w h a t is b e i n g d o n e
Table 2 Summary of selected direct and expected benefits
Construction project Selected direct and expected benefits
Low-income housing project with a total of
324 units (3 months of research time)
Mid-income housing project with a total of
30 units (2 months of research time)
Mid-income housing project with a total of
2000 units (1 year of research time)
• 10% increase of productive labour time
• 40% increase in productivity of concreting crews
• Improved construction methods
• Reduction of rework
• Reduction of wasted time
• Increase of productivity through a better balance between construction operations
• Reduction of construction major cycle time
• 25% increase of productive labour time
• Reduction of housing units construction costs
• 70% reduction of clients’ complaints due to low quality of product
Construction process improvement methodology for construction projects: A Serpell and L F Alarc6n
and achieved. It is interesting to note here that many
construction managers that have participated in
improvement processes have incorporated the concept
of continuous improvement in their management style,
permanently pushing for new ideas and improvements.
Third, the experiences, lessons learned and implemented improvements have been incorporated into
normal procedures and methods of many companies, a
fact that has produced an accelerated change of the
Chilean construction technology during the last
5 years. Also, this experience has been documented
and published by researchers to make it available for
other construction companies and projects.
Additionally it has helped researchers when undertaking new construction improvement processes.
An structured framework for the improvement of the
construction process has been presented. This methodology has been very effective in achieving significant
improvements in several construction projects. The
framework has been developed from repeated experiences of supporting construction companies and projects in their improvement efforts.
The use of a structured framework provides systematic information gathering about the construction
process and a sequence of logical steps based on a general problem solving approach that increases the potential of a successful improvement project. Also this
approach allows repeatability and reliability of
improvement efforts that can be fed back with experiences and lessons learned from previous projects.
In addition to the framework used for improvement,
there are some requirements that are necessary for
achieving good results. One of them is obtaining commitment of all the people involved in any improvement
effort. Without their support and participation it is not
possible to achieve improvements. A second important
requirement is to carefully plan the implementation of
improvement actions. This stage is by far the most difficult and complex one and should be seriously studied.
Within the framework it is very important to select
the appropriate tools and methods to carry out the
improvement activities. Experience plays a very important role in this respect.
The authors would like to acknowledge the contributions of the Productivity and Management Service
of the Pontificia Universidad Cat61ica de Chile, which
conducted the studies presented in this paper and of
the Corporaci6n de Investigaci6n de la Construcci6n
(Construction Research Corporation) which supported
1. Alarc6n, L. F., Training field personnel to identify waste and
improvement opportunities in construction. In Lean
Construction, ed. L. Alarc6n. Balkema, Rotterdam, The
Netherlands, 1997, pp. 391-402.
2. Serpell, A., Venturi, A. and Contreras, J., Characterization of
waste in building construction projects. In Lean Construction,
ed. L. Alarc6n. Balkema, Rotterdam, The Netherlands, 1997,
3. Straker, D., A Toolbook for Quality Improvement and Problem
Solving. Prentice Hall, Hemel Hempstead, UK, 1995.
4. Oglesby, C. H., Parker, H. W. and Howell, G. A., Productivity
Improvement in Construction. McGraw Hill, New York, 1989.
5. Ghio, V., Serpell, A. and Alarc6n, L, F., Reducing construction
waste: first step in order to house a nation, the Chilean experience, In Proceedings XXIVth. IAHS Worm Housing Congress
Ankara, Turkey, 27-31 May, 1996, pp. 663-673.
Afredo Serpell is Associate Professor
of Construction Engineering and
Management at the Catholic
University of Chile. He teaches project planning and management, construction productivity improvement,
construction quality management and
construction proeurement. His current research interests include quality
management, productivity improvement, lean construction and construction procurement practices in Chile.
Since 1990 he has directed and managed a university-based consulting
group that provides services to the
Chilean construction industry and has
been actively involved in the promotion of continuous improvement of
this sector. He obtained a Civil Engineering DegreeJ~om the Catholic
University of Chile and a M.Sc. in Architectural Engineering and a
Ph.D. in Civil Engineering from the University of Texas at Austin,
Luis Fernando Alarc6n is currently
Head of the Department of
Construction Engineering and
Management at the Catholic
University of Chile. He received a
Ph.D., a M.Eng. and a M.Sc. in Civil
Engineering from the University of
California, Berkeley. His teaching
focus is on project planning, project
management and risk management.
His research and consulting activities
concentrate on: performance
improvement in construction; project
risk analysis; strategic planning for
construction companies; and decision
support methodologies for construction projects. He has conducted
research for government and private agencies in Chile and for the
Construction Industry Institute in the USA.