Introduction to continuous improvement methodology in construction

In the construction industry for any project multi parties are involved who have their own goals, objectives, and expectations. For example, clients may expect project completion underspecified specifications and time while the management team will be concerned about the project planning and procurement, also the contractor will be concern about the safety and the quality of construction. These interested parties pileup and form a complex web for an organization to handle.

Such complexity can only be solved if a plan is finalized before the execution of a job. The construction industry is adapting itself to major changes by focusing on proactive problem-solving approaches. These approaches may vary but the focus is to eliminate or reduce the imminent threat of quality loss and continual improvement of the process and system.

These approaches tend to eliminate or reduce the probability of risk at its root-cause level. Even if the problem occurs, the solution can be provided easily using these approaches. Meanwhile, using these approaches helps us utilize the opportunity to understand the root cause of the risk & adapt the system to avoid future confrontation with it. This leads to continual improvement in the system through real-time data-driven techniques.

Some of the prominent approaches in the construction industry are Kaizen Approach, Six- Sigma Approach, Lean Approach& PDCA Cycle. These approaches were firstly adopted in different industries with a controlled environment. The adoption of them in the construction industry has different interpretations as it has a vast number of approaches& the environment is not controlled. So, these approaches have to be modified based on the construction industry.

Below is the brief on how we can use different approaches in the construction industry:

Kaizen Approach

The definition of kaizen comes from two Japanese words: 'kai' meaning 'change' and 'zen' meaning 'good'. This concept was first introduced in the1980s by the Japanese car company, Toyota. The company aimed to develop a business model that catches errors in quality as soon as they occurred.

The process focuses on continuous improvement techniques rather than strength or intelligence. The process sees the potential of improving mistakes &efforts to reduce errors in the procedures.

Kaizen is a six-step continual improvement procedure

1.  Discover improvement Potential

2.  Analyze current methods

3.  Generate Original Ideas

4.  Develop Implementation Plan

5.  Implement the plan

6.  Evaluate the new Method 

How is Kaizen used in Construction?

Since the above concept was developed for the manufacturing process in a controlled environment, it required modification when applied to construction. Since construction process depends on many factors such as environment, materials, the procedure followed & vendor/contractor. Thus, for construction kaizen became a pro-active management approach that maximizes project value and minimizes waste.

Kaizen focuses on reducing non-conformance costs. Non-conformance costs are costs that are aby-product of poor quality achieved in construction. Kaizen method focuses on avoiding waste resources & identifies and eliminates the root cause of the wastage by total involvement of employees of all levels.

There are many tools used in the kaizen method to improve quality & reduce cost in the construction process. These tools are discussed in detail in a further blog.

For example, if an activity is conducted under the supervision of a specific person &always results in a lack of quality. The conclusion using the kaizen method can be reached that either the person lacks in carrying out the activity properly or he/she might need some training to carry out the activity as described. Also, there can be a debate on how he/she is not provided enough resources to carry out the specified activities. Before coming to any conclusion the root cause is found based on data analysis & real-time checking.


Six-Sigma Approach

The name Six Sigma is derived from the bell curve used in statistics where one Sigma represents one standard deviation away from the mean. It was introduced by an American engineer working for Motorola Company in 1986. Six Sigma is a measurement-based strategy for process improvement. It has followed the principle of the DMAIC Model for Quality Improvement. It is an integral part of the Six-Sigma Approach but can also be used as a stand-alone process in a quality implementation.

DMAIC Model approach is as follows:

1.  Define the problem

2.  Measure key Aspects

3.  Analyze the Data

4.  Improve current Process

5.  Control the future Process

How is Six-Sigma Process used in Construction?

Construction Project which uses a six-sigma approach aim at reducing & removing defects. Defect by definition is, not only rework or wastage but also inability to provide customer’s satisfaction. Six-Sigma’s Control phase is specifically helpful to contractors & managers to strengthen their financial aspect.

The main aspect of this process is to maintain flow & manage resources like material, time, capital & manpower. This is also a continuous improvement procedure applied to achieve the highest efficiency in construction.

For a construction site, the six sigma methodology decides key aspects such as site logistics, buying raw material, moving raw materials to the desired location, allocation of labor to any activity & defined time. For example, masonry has to be done on the second floor of a building on a specific day. through the six sigma approach, a contractor can buy material in advance & unload it to a location. Then when an activity needs to be carried out, materials is available in desired location be forehand. This reduce the time of doing work as material is available at the location where shortest time is require.

Lean Approach

This method again has roots in Toyota Motors. This method was developed in the 1920’sbut was not implemented until after World War-2. This approach was first coined by the international group of Lean Construction in 1993. It was initially adopted for the manufacturing process in a controlled environment but its success led to adopting this process in a wide range of industries.

Lean Approach uses a wide variety of tools such as Last Planner System, Integrated Project Delivery, Kaizen Approach &Building Information Modelling. It has a wide range of tools present in the system which can be applied which helps in providing a holistic approach for project management.

It has 6 principles as follows:

1.  Identify Client’s Value

2.  Define Value Stream

3.  Eliminate Waste

4.  Streamline Workflow

5.  Implement Pull Scheduling

6.  Achieve Continuous Improvement

How is it used in Construction?

Lean construction was adopted by contractors & management firms due to the high success rate. Lean construction transforms every stage of construction by demanding the involvement of workers from all levels, training needs, and expressing innovative ideas for a problem at hand.

It has helped in achieving on-time delivery of projects, increased customer & worker satisfaction, high quality, and better risk management procedures. Lean Construction is a popular idea for management firms to provide complete customer satisfaction & building a prestigious reputation.

The lean approach helps in bringing every level of stakeholders from architects to subcontractors & suppliers close. The process are well defined in advance which will eliminate extra effort of any stakeholder.

PDCA Cycle

PDCA Cycle was first developed by a management consultant Dr. William Edward Deming's in the 1950’s. It is also popularly known as Deming’s cycle. This model helps in building a continuous loop for controlling & improving processes.

It helps in implementing a total quality management system through its four principles. This basic nature of the model helps continual improvement easily available and understandable for clientele.

Four principles of the PDCA Cycle are:

1.  Plan the activity: Identify opportunities or errors

2.  Do: Implement a process for risk elimination or grabbing the opportunity

3.  Check: Analyze data & results of the process

4.  Act: Either accept the procedure or improve for better quality achievement.

How is it used in Construction?

PDCA Cycle has a wide variety of applications in the construction industry. It can be used as a total quality management system. It is easily applicable in the construction industry due to its basic nature.

PDCA Cycle generally helps the organization build quality products, guarantees customer satisfaction, and helps in continual improvement through data-driven analysis. It also helps in guarantee that the mistake is not repeated in any further processes. Along with this's it also has a feedback system in place that helps remove any communication gap between different workforce levels. This makes the workforce active in providing innovative solutions in their respective aspects.

PDCA Cycle can be demonstrated for precast concrete activity. After casting of members, testing and checking of members is done as per specification and drawing or not. If a member is found okay as per specification and drawing, no further action is required but if in case any deviation is found, root cause analysis is to be done for material quality, workmanship, etc. to find out the issue. This issue is then corrected and so the same issue is not encountered. This helps to reduce wastage and rework.


The below table gives a general idea about how every model discussed above is

different from one another and how they are implemented. Overview of each system gives a basic idea to one about choosing the appropriate quality management approach. It depends upon the complexity& nature of the development project. Many factors affect this decision& data-driven analysis is generally preferred for selecting one.  

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