Root cause analysis is done to determine the main cause of the error or problem caused during the process. Root cause for the out of specification, deviations during manufacturing and market complaints must be determined. Different methods are used for root cause analysis in pharmaceuticals.
5 why is a useful and effective tool to identify the root cause during the manufacturing or analysis of drug products. Simply ask the question and try to find the exact answer for that. When the root cause of the error or problem is identified then it is rectified for the good. Many FDA warning letters are issued because root cause is not analysed for the deviations.
5 why tool is a set of the five questions to reach the base of the problem but some time more than five questions may require. Ask question for the problem caused and answer. Ask the question using 'why' again and again repeatedly to travel towards the root until you find the correct root cause.
More than half of the problems in the process is occurred due the the human error but human error is not a root cause in all the cases but it is a symptom of the other problem. When these human errors are investigated further other problems appear having root cause.
For example – If an operator of a compression machine suddenly stops the machine during the compression process. The root cause of the problem should be identified. When we apply 5 whys, we get the following answers.
1. Why did the compression machine stopped suddenly?
A human error occurred.
2. Why did this human error occur?
Operator hit the emergency stop button.
3. Why did the operator hit this button?
The label on the button was not clear.
4. Why was the label not clear?
Labels were covered with the dirt.
5. Why the labels were covered with dirt?
Machine was not cleaned properly.
Using the 5 why tool we got the root cause of the sudden stop of the compression machine because the compression machine was not cleaned properly and the operator was unable to recognize the stop button. Root cause analysis also helps to implement the corrective and preventive actions effectively.
Fill up the deviation or incidence report for this incidence and prepare a system to cross check the cleaning of the machines daily to prevent the happening of the same in future again.