Human error in manufacturing becomes more and more visible every day that technology continues to advance. In fact, it is responsible for more than 80% of process deviations in pharmaceutical and related manufacturing environments. Why then is so little understood about the nature of these events? Primarily because quality event investigations end where human error investigations should begin.
Those who work in an industry where good manufacturing practices (GMP) apply need to address human error deviations. The reason, as I explained in this blog post, is not only because they are a hassle, but because the regulations require it.
The Code of Federal Regulations (CFR) Title 21 subpart B, Organization and Personnel Sec. 211.22 “Responsibilities of quality control unit” states “(a) There shall be a quality control unit that shall have the responsibility and authority to approve or reject all components, drug product containers, closures, in-process materials, packaging material, labeling, and drug products, and the authority to review production records to assure that no errors have occurred or, if errors have occurred, that they have been fully investigated.”
It’s essential to note the section of the sentence in bold above. Human error is NOT a root cause because it may be the reason for the error, but it doesn’t fully explain why the error occurred.
The European Commission’s “Rules Governing Medicinal Products in the European Union, Volume 4, EU Guidelines for Good Manufacturing Practice for Medicinal Products for Human and Veterinary Use” Section 1.4 is slightly more specific. It states, “A Pharmaceutical Quality System appropriate for the manufacture of medicinal products should ensure that: (xiv) An appropriate level of root cause analysis should be applied during the investigation of deviations, suspected product defects, and other problems…”. It continues, “Where human error is suspected or identified as the cause, this should be justified having taken care to ensure that process, procedural or system-based errors or problems have not been overlooked, if present. Appropriate corrective actions and/or preventative actions (CAPAs) should be identified and taken in response to investigations. The effectiveness of such actions should be monitored and assessed, in line with Quality Risk Management principles.”
During the investigation of a quality event, the primary goals should be to:
A human error in manufacturing usually explains the reason for a deviation’s occurrence. However, it’s unlikely that the reason for the error was explained. Consequently, CAPAs often fail to address the underlying conditions for failures. This, in turn, translates into ineffective action plans that result in non-value-added activities, wasted resources, and – inevitably – repeated events and recurrences.
You can’t understand the underlying causes of human errors in manufacturing without explaining human behaviour. Chemical engineers explain product behaviour, industrial engineers explain process behaviour, and mechanical engineers explain equipment behaviour. But who explains human behaviour?
Just like equipment, products, and processes, human behaviour is complex and must be analysed equally as extensively. No one would ever end an investigation with only “equipment failure.” The persons responsible would explain exactly what the equipment failure was so it could be fixed.
Events caused by human errors in manufacturing must be fully investigated to assure CAPA effectiveness. Regulations require that errors be fully investigated, which means you must identify the reasons why they occurred. To meet this expectation, we must understand how human behaviour is affected by external variables as well as internal variables.
First, we need to understand what a human error in manufacturing is. Human error is defined in many ways. One definition that I like is “any action, performed by a person, which exceeds a system’s tolerance.” Human error is a mistake – not an act intended to harm. Sabotage is not considered a human error unless the result of the actual intentions differs from what was expected. Therefore, saying that a human error in manufacturing has occurred does not necessarily mean that it is the “human’s” fault. Also, a current Human Error Rate needs to be established. Human Error Rate is a simple calculation but most companies don’t measure it correctly. The formula for calculation is:
Number of Errors⁄Opportunities for Errors
Once that calculation is in place, you are ready for reduction.
As humans, we don’t operate in a vacuum. Behaviours are influenced by external as well as internal variables. In manufacturing environments, these variables can be divided into six major categories:
Individuals are undoubtedly responsible for their actions. But before we determine that internal factors like attitude or attention are accountable for a human error in manufacturing, we as organisations are responsible for eliminating the possibilities of external factors influencing human behaviour. Individual performance in manufacturing is proven to be responsible for less than 5% of deviations. If an employee overlooks defects because of a lack of appropriate vision, for example, shouldn’t the organisation make sure visual exams are performed regularly? Even in this example, we can see that a “fit for duty” system is tenuous.
On the other hand, training is usually used as a corrective action. Although training has proven to be effective for transferring knowledge, skills, and abilities (KSAs), it will only work for new employees, new processes, or to instruct on changes to existing processes if the employees who perform the task lack the new KSAs. In fact, training is responsible for less than 10% of the deviations related to performance, yet most of the organisation’s efforts are directed toward less than 10% of the actual weaknesses. It’s no wonder that training-related CAPAs are often so ineffective.
The most effective way to control human error in manufacturing is to implement adequate systems. Purpose-built systems take care of human factors (any aspect of the workplace or job implementation that makes it more likely for the worker to make an error) and external factors. We can start by:
It’s critical to know the difference between explaining an event and explaining a human error in manufacturing. Once the human error has been identified as a cause for the deviation, consider the human error itself as a new event that needs to be explained and examined to assure conditions are identified and fixed.
If changes are not made, past behaviour will predict future behaviour. We must perform assessments of past events and assure the reasons for the error, besides the reasons for the event, are identified. Then we need to categorise these causes (conditions for error) in a systematic and uniform way. This makes it possible to analyse significant contributors and, based on priorities, create an action plan that addresses the conditions. For example, if most of your human error events were related to incomplete procedures, then revising them and adding the missing instructions would be an action to consider.
Human error in manufacturing will not be eliminated unless we can truly identify what is causing humans to make mistakes. If “fixing” the actual individual eliminates or potentially reduces the probabilities of making that mistake again, then addressing the employee would be effective. If we challenge ourselves, we can’t categorically assure that this will correct the problem. Intervening with the individual will only create a liability to the organisation, and we will end up back at the beginning, trying to correct a different individual’s same mistake.
What do organisations need?
Eliminating the conditions (causes) that make people deviate from the expected outcome will make CAPAs more effective. Therefore, CAPA effectiveness should be measured by root cause recurrence and event recurrence. Most events, although different in nature, share the same causes. Real CAPA effectiveness will be achieved when the number of deviations decreases – not when particular events fail to reoccur.
This way, we will be more productive and fairer to those who work to do a good job but end up being victims of weak systems.
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