There are many ways to use structured problem solving to solve problems and make improvements. Oftentimes different organizations have different methodologies they prefer, they will likely even have different methodologies they apply depending on the type problem at hand (i.e. cost savings follow an A3 approach while quality issues are solved using an 8D). Since the company will likely offer detailed training on their preferred methodology, the intent of this question isn't to determine if the candidate is an expert at a specific problem solving approach. Rather, the question is used to determine whether the candidate has experience using a structured methodology to solve problems. It is common for western-thinkers to focus on solutions before they fully understand a problem, for a CI engineer it is imperative that a problem is fully understood before a solution is generated. This is an ideal time for the candidate to demonstrate their understanding of cause and countermeasure thinking.