5. Comparison and synthesis

The methods we have just briefly presented have been successfully applied by many companies, even if it is often difficult to properly measure their contribution in terms of availability, financial benefits, or improved operating safety. They were developed for a particular type of industry (aeronautics, nuclear power plants, the automotive industry, etc.), based on a national culture. They were then adapted to other sectors and countries. Without entering into detailed comparisons, we can give a few general ideas that enable us to group them together, contrast them, or show how they complement each other.