What is SCRUM
SCRUM methodology was invented in early 90s. The precursor's idea was to create a process of building software in a structured and iterable way. The main goal of SCRUM is to meet the new business' requirements in the rapidly changing world.
SCRUM in theory
SCRUM by definition is an agile software creation methodology. For the customer, it means that he can react to any business change in time, not after the software product is finished and deployed, but still during its development process. Short iterations and continuous validation is the biggest power of SCRUM. That is why it is much better than old-school methodologies like Waterfall.
SCRUM vs code quality
Because of its nature, SCRUM forces the development team to deliver in a predictable manner. Every sprint starts with the planning ceremony, when developers commit how much they can deliver. After that, the sprint goes on and there is no space for mistakes during the implementation. Every hour spent on unexpected issues result in overdue. Usually, the team wants to deliver what they committed to. Because of that everything else has lower priority. Including code quality.. The goal is to deliver sprint.
SCRUM is a great software development methodology – especially in case of ordering the software from vendors. It allows having a clear overview and good development progress tracking. The problem is that SCRUM is interpreted by software vendors only partially. SCRUM is sold as a business tool only. Key terms like "Definition of Done" are skipped. Which unfortunalety later may result in outgoing projects and rising costs.