[Total: 2    Average: 5/5]

The HERCA methodology is a simple tool to identify the root cause of human error and set up a countermeasure.


The WCM methodology provides a structured method for removing human error. When human error is one of the potential causes of the problem, we will use the HERCA analysis, H uman E rror R oot C ause A  nalysis, to identify what is the root cause and how to eradicate it.

It is recalled that as in the Lean 6 Sigma approach, the philosophy of the WCM is based on never judging / blaming an operator.

Step 1 – Perform the TWTTP interview

At first, we will rely on another tool specific to the WCM that is the tool TWTTP. It will allow an assessment to be made of a person’s ability to perform a task.

Step 2 : Identify root cause

The TWTTP analysis pointed us to one or more types of human error. Depending on the cause or causes, we will implement one or more types of actions to avoid the problem according to the following table :

Group of causes

Name of the cause


Actions to put in place


Lack of skills

Lack of training or repetition of training

Training, Standardization, Visual Management, One Point Lesson

Lack of understanding of instructions or training

Lack of experience at the workstation

Specific work to do only rarely


Problem with standards

Instruction not clear

Standardization, One Point Lesson

Incomplete instruction

Lack of education

Environmental condition

Too much light, noise or vibration

Ergonomics, 5S

Problem with the process

The process is too complex

Poka Yoké, 5S, Standardization, One Point Lesson

The process can easily generate non-quality

Problem with the organization of the workstation

Efforts are too important

5S, Ergonomics, Gemba Kanri, Standardisation, Visual Management

The space is poorly arranged creating complex postures.

The rules for using space are not respected.

Technical problem with the equipment

Machine or tools are not suitable for work.

5S, Poka Yoké, Process design

The machine generates default design faults.

The procedures for using the tools and the machine do not exist.

Appropriate tools are not always available.
Behavior Problem to follow instructions An error was made due to lack of attention. Poka Yoké, Standardization, Visual Management, Gemba Kanri.
The staff made a mistake because it is a very repetitive task.

Staff did not follow instructions.

Personal situation

Stress, fatigue, health problem.

Provoke involvement, Provoke motivationErgonomics

Lack of motivation and involvement.

Step 3 – Repeat a TWTTP analysis

At this stage, we have identified the root cause of the error and we have implemented one or more actions to eradicate it. We will redo the initial analysis to see if the score has improved.

Step 4 – Approval

At the end of the activity, we will close the HERCA by signing the production manager who will validate the quality of the countermeasure.

Step 5 – Follow up

Each day / month, trends in the number of open and closed HERCA will be tracked. This will validate the long-term quality of our actions.

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