Corrective & Preventive actions are two most common actions identified as a part of doing a Good Why Why Analysis of 5 why analysis, which is done as part of Root Cause Analysis.
Many users & trainers on Root cause analysis do not understand the real different between corrective and preventive action.
Corrective Action: in most of the cases, what is considered as a Corrective action is actually Immediate Action or Band-Aid Solution. For example: If a part is broken, replacing it with a new part is considered as corrective action, which is technically incorrect. Replacing broken part with a new part is actually a Band-Aid Solution and does not require any kind of analysis or problem solving work. Corrective action is action which will element the root cause/s of the problem within a particular equipment or particular area of problem. In simple words, once corrective action is implemented, problem should disappear from selected problem area.
Preventive Action: Preventive action is an action, which will eliminate the problem completely from entire organisation or entire area of operation. Generally corrective action is considered as preventive action, which is technically wrong. Preventive action, once implemented, will eliminate problem completely from entire organisation.
Lets take an example to understand difference between Corrective & Preventive action. Printing machine in a Flex Printing organisation was breaking very often due to failure of gear on one of the printing roller. After Root cause analysis was done, it was identified that ink mixing with lubricants used was resulting in choking of gear, thus breakdown of the gear. Ink was splashing and getting mixed with the lubricants due to poor viscosity, which was due to no standard present or followed for maintaining ink viscosity. Lack of standard was identified as a root cause, a process was created to ensure if standard is not followed, job can not be started. Implementing the process of following this standard only one machine is called Corrective action. When same action is implemented in all printing machines within organisation, it becomes a preventive action, which will avoid problem completely in whole organisation.
Identification of Corrective & Preventive action requires following systematic process of Root Cause analysis. Using techniques like Brainstorming with team members, understanding & observing problems at Gemba makes it easier to identify Corrective and preventive actions. Each action identified should be based on data and facts, which have been thoroughly verified.