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Construction Safety

Innovations in Construction Safety—Error-Proofing

Peter Furst | August 1, 2012

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Building inspector at a construction site

Construction safety traditionally focuses on the worker for reduction of accidents and improvement of outcomes. Though the worker, who is at the "sharp edge," performs the final act resulting in an accident, there are often multiple contributing causes that may be overlooked or not seriously considered. Most accident investigations and root cause analyses fail to get at the reason for the decision made by the worker to do what he or she did at that crucial point in time.

A review of typical safety interventions produces a list that will include programs, training, meetings, talks, postings, inspections, incentives, punishment, etc. These have been in use since the enactment of the workers compensation laws, some going back about 100 years. To this we can add the Occupational Safety and Health Act, which has been around more than 40 years, as well as various forms of behavioral interventions, which have been around for about 35 years. While all of these laws and interventions certainly have contributed to the reduction of construction incidents and accidents, they have not eliminated them.

Identifying the Source

Most defects or incidents in the construction process are caused by some form of human activity. Often, those involved in the process may not be aware that they contribute to the problem, or they may be aware but fail to respond properly or effectively. Some may lack the information, capability, or knowledge. Others may fail to adequately understand or evaluate the level of exposure or consequences of their actions.

Construction error can reduce productivity, result in poor construction quality, or cause injuries to the workforce. It is estimated that anywhere from 2 to 10 percent of the gross cost of a project is wasted due to such errors. Errors may contribute to the incidents or accidents, which cost the industry $50 billion or more annually, and the traditional tools and techniques used to reduce accidents are not effectively and positively affecting this enormous cost. The resulting numbers of accidents or losses may be viewed as the "defect rate" of the operating process.

What most of the folks implementing safety interventions fail to address is why the worker chose to do what he or she did. The construction industry can benefit by taking a page from manufacturing, where error-proofing has had a great impact on reducing the rate of defects.

To reduce work errors, the contractor must incorporate error-proofing into the way business is carried out, the organization is structured, and the operational processes is performed, such as in partner selection, operational planning, task risk assessment, and execution. Following are six potential outcome improvement or error-proofing techniques:

  1. Elimination seeks to eradicate the error-prone process step(s). This may involve redesigning the building elements to make them easier to build or maintain. Or it may require the rethinking of the work practices to eliminate the risk of making a mistake.
  2. Substitution identifies more reliable processes to improve error-free execution. This involves exploring the uses of alternate processes to diminish exposure and the potential for mistakes.
  3. Prevention redesigns the structure's elements or modifies the operational process or work procedures to reduce potential error-causing action.
  4. Risk reduction seeks to simplify the process, minimize exposure, or ease its execution. Prefabrication, preassembly, or standardization helps reduce exposure and the potential for making mistakes.
  5. Detection is aimed at early identification of mistakes to assist the operator to correct performance. This requires an analysis of the operational processes, task procedures, or work practices for error causation as well as peer reviews and performance/execution observations.
  6. Mitigation tries to minimize adverse effects of the error. Since humans are prone to make mistakes and systems can degrade, errors are inevitable. So, this step tries to immunize the adverse effects of such an outcome. This may involve preoperational planning, pre-task activity review, self-checking, pairing of people, etc.

After a number of high-profile accidents in the 1970s, the airline industry searched for ways to improve operations. Those people recognized that human errors were a causal factor in many of the accidents and developed the crew resource management (CRM) process, which teaches teams to make optimum use of all available resources—equipment, procedures, and people—to promote safety and enhance the efficiency of flight operations.

If we boil the organization's operational process down to its most elemental state, an output (building) is created by the use of the construction company's systems (processes, practices, and procedures), and these are activated and managed by the people (workers, supervisors, managers, and executives). Looking at this model, there are only two major sources of potential error or loss, and these are either in the systems or in the people. Unfortunately, in construction, the focus is primarily on the worker part of the people segment, resulting in trying to eliminate the problem by addressing only a small fraction of the whole. This is the underlying reason for the lack of greater success in a more substantive reduction of the negative safety outcomes.

Instituting Error-Proofing in Construction Projects

Mistake (error) proofing is a powerful tool adopted by the manufacturing industry to increase the quality of its products, improve efficiency, and reduce cost. Construction is also a production process, and many of the error-proofing tools and techniques used in manufacturing are applicable. The following steps can be useful in the effective implementation of an error-proofing process into construction.

  1. Create a cross-functional team to evaluate the existing systems and identify error-proofing opportunities. The team should include representatives from all levels of management, departments as well as producers (workers) and key subcontractors' personnel, if necessary.
  2. Devise standard procedures for error-proofing the organizational, business, and operational systems so that they are easy to use, generate results, foster involvement, and are sustainable.
  3. Utilize a structured problem-solving methodology to isolate problem areas and determine the most effective way to improve performance.
  4. Value stream mapping can be used to identify areas where improvement is necessary and to ease implementation.
  5. Select the most effective and appropriate solution after a thorough review and analysis of the issues and constraints involved. Utilize the six progressive steps listed above.

Error-proofing all of the company's systems is an important step in increasing efficiency, improving quality, enhancing productivity, increasing job satisfaction, facilitating safe execution, and improving profitability.

Another thing to consider is that in the traditional (worker) intervention practice, the underlying assumption is that the worker has total control and therefore can resolve the problem. This cannot be further from the truth; the worker has to function within the overall operational system. Yes, the worker can control his or her action and maybe exert some influence over the immediate area, but a vast number of extenuating conditions and circumstances influence the outcome. Management controls the "big picture" (strategy, goals, objectives, schedule, cost, etc.). At the operational level, management selects the worker, assigns the task, provides the tools and equipment, makes assignments, supervises the work, etc. So, if management places the worker in a predicament where the production goals conflict with safe procedures, the worker may choose production in order to stay employed. This speaks to internal alignment and system integration, which are controlled by management. Therefore, management can greatly influence the error-proofing of operations and improve the worker's success rate.

Dan Petersen said that "Incidents are caused by the combination of management system failure and human action or error" and "Human action or error may also be caused by management created environments that reward risk taking."

Classifying Defective Performance

The sources of discrepancy or injury risk can be the individual worker, the systems, or the interaction of the worker with the system, since the worker has to successfully function within the organization. First, let's look at the individual worker and what may affect safe performance. Below are some general classifications that may lead to "defective" performance. This list is by no means complete and may differ for different organizations.

  • Capability: Physical strength, dexterity, experience, competence, skill, talent, etc.
  • Knowledge: Lack of information, lack of understanding, intelligence, miscommunication, incomplete information, misinterpreting memory, etc.
  • Judgment: Prejudice, expectation, perceptiveness, acumen, assessment, misjudgment, etc.
  • Attentional: Lack of focus, breaks in concentration, interruptions, disruptions in flow, overcrowding, multitasking, focus, etc.
  • Mistakes: Slip, lapse, forgetting, incidents, oversight, deviation, perception, etc.
  • Personality: Habit, confrontational, deciding to ignore rules or standards, arrogance, over-confidence, risk taking, disruptiveness, stubbornness, etc.
  • Motivation: Activate, persuade, reason, impulse, cause, induce, influence, etc.
  • Intentional: Deliberate mistakes, personal agenda, sabotage, etc.

Each of the above categories provides a different approach to risk reduction and error-proofing the operation. These originate with the worker, but most of the solutions have a management or system component. Management can design systems, devise processes, or implement procedures that are error proof. An example of error-proofing where the systems make it impossible to make a mistake is the USB plug: you cannot install it backwards as it has a failsafe configuration. Likewise, management can devise systems that either eliminate or significantly reduce the error-making potential.

The traditional way of dealing with error was to scold the offender, tell them to be careful or pay attention, or retrain them. Training is only useful in cases of knowledge deficiency. It is a proven fact that humans make mistakes, and training does not correct or change this. Some research findings indicate that humans make five or more mistakes per hour. And, since we cannot change human nature, we should actively try to remove error-making possibilities or mitigate the potential results of the mistake. Motivation, feedback, and training work best if and when the physical environment as well as the systems and expectations are well designed and do not provoke errors. There really is no way the organization can expect to achieve excellence unless the systems facilitate ease of execution, reduce required effort, and enhance flawless achievement ... while promoting safety.

The system may create situations that increase the potential for making mistakes. So, the design of the project, construction process, or procedure and the organizational systems must be reviewed for such possibilities. There are also problems in the lack of a robust process for the design and construction interface, which leads to suboptimal solutions. The lack of constructability leads to a large number of change orders (design and construction rework). Generally, design defects come to light during the construction phase, putting the error detection controls downstream. This is contrary to accepted error-proofing thinking and practice. Therefore, the owner and the designers should partner with the contractor as well as key subcontractors to move the error-proofing process upstream to eliminate waste and the causes of potential defects. It is a known fact that there are error-provocative design solutions, and these should be addressed with the owner, architect, engineer, and contractor for resolution.

As far as construction is concerned, it is a "low-productivity, high-waste" industry compared to many others. Though construction has its own peculiarities, technical as well as system changes can transform it so that overcoming some of the intransigent barriers becomes a real possibility. Some of this is attributable to error-provocative conditions that are created by the organizational systems of the contractor, but here we are going to address the project processes, procedures, and practices for potential error-proofing. After all, construction is fundamentally a production process, and processes can be optimized.

Before a project is finalized, the preconstruction team and the potential project team should review their operational, tactical, and logistic plans, the project schedule, budget, the procurement plan, subcontractor selection, staffing, controls, etc., for error-provocative potential. This early investment of resources will ultimately have a tremendous impact on the reduction of variability, uncertainty, inconsistencies, and constructability, leading to substantial efficiencies and elimination of waste and injuries.

An assessment of the project systems should first look at the project team and ensure they have all the necessary capability, knowledge, and motivation and that they can and will function as an effective team. All potential deficiencies should be addressed and mitigated prior to start of work. The systems critique starts with a review of all the potential processes, procedures, expected practices, and performance expectations that will be in effect, utilizing the framework of steps listed above. System error-proofing guidelines include:

  • 1. Make "doing it right" the first time an organizational "living" core value.
  • 2. Devise robust systems that enhance error-free performance:
    • Utilize shop prefabrication over field installation where possible to reduce error.
    • Use preassembly to reduce exposure time.
    • Incorporate modularization to foster ease of installation.
    • Standardization can help reduce task difficulty/variability.
    • Utilize checklists and use them every time the activity or situation changes (similar to CRM).
    • Anticipate deviations, fluctuations, and changes in flow with "ready" preplanned interventions.
    • Minimize disruptions so as to reduce distractions and focus attention.
    • Have recovery plans ready for use for potential disruptions or failures.
  • Utilize a team environment that promotes open participation and leverages experience in the continuous improvement process.
  • Employ planning, risk assessment, and problem-solving methodologies to drive performance to perfection and defects to zero.
  • Implement a continuous improvement process supported by an organization-wide sustaining system.

Once the systems are optimized, the next step is to address the interaction of the people with the systems. This is the understanding or perception of the people who are operating within the operational systems and their understanding of what is expected of them. They may misunderstand or draw the wrong conclusions and so act in ways that are not in the best interest of the organization. Some of these problems may result from communication or information that is not clear, insufficient, untimely, or confusing. Management must ensure that workers have a clear understanding of expectations. Mistakes may occur because of:

  • Perception errors (misunderstanding, misreading, misidentifying, misjudging, etc.)
  • Communication (ambiguous, incorrect, incomplete, untimely, etc.)
  • Expectations (speed, production goals, performance, compliance, task demand, working too slow, trying to catch up, being overloaded, etc.)
  • Influences by others (failure to deliver as promised, lateness, shortage, defective part, etc.)
  • Task assignment that ignores worker capability (strength, experience, skill, competence, proficiency, etc.)
  • Poor planning or risk assessment (which increases variability, uncertainty, pressures and stress, surprise, etc.)
  • Failure to assess worker knowledge (lacking experience, training, skill, etc.)
  • Not controlling the environment (stress, noise, heat, cold, lighting, risk, etc.)
  • Motivation (influence, desire, activate, persuade, stimulate, perform, etc.)


There are as many mistake-proofing strategies as there are mistakes. A holistic approach to mistake proofing requires communication and cooperation between the producers (workers) and supervision. The internal systems have to be fully integrated and aligned with business goals and objectives. Managers must become leaders to empower and motivate the workforce to become fully engaged in improving the processes and practices. The culture and climate must support and sustain the error-proofing procedures and the worker-system interface. Error-proofing must become an organizational value and "way of life."

The error-proofing approach can have a much broader impact on the construction process than just reducing or eliminating worker injuries. Studies have determined that anywhere from 40 to 65 percent of the cost of construction does not create value for the project owner. Whatever percent may be the true reflection of this waste, it is a waste, and every effort should be made to address this. The error-proofing process defined above looks at the three key areas where the risk of defects may occur in the organization's systems, business practices, and operational process as well as the behavior of the people within it. If error-proofing is integrated into the organization's "means and methods," the potential benefits are going to improve the company's reputation, give it a competitive edge, and improve its bottom line.

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