Business analysis is a discipline that requires an array of knowledge, such as business domain expertise, effective communication skills, stakeholder management, navigation of technology landscape, deep understanding of stages within system development life cycle (SDLC), and future proofing intuition honed by experience.
A good business analyst must be able to do more than methodically working through various stages of an Agile framework like Scrum or a traditional method, such as waterfall. Being able to handle the very first meeting with the business to set correct expectations requires a very good understanding of both business and technology architecture. Why? Because without such knowledge, inaccurate expectation may well be set that could lead to not only misalignment between business needs and organisational capabilities, but potential deviation from the organisation vison.
A competent analyst can circumnavigate the business terrain, the IT landscape to save the business tangible money, because it is much cheaper to document a solution on paper than building one. Delivering the right solution, that adds value to the business, inline with organisational objectives, with no hidden architectural conflicts cost less than committing budget and resources to a potentially wrong or incomplete solution .
As far as the general ability is concerned, a business analyst works across the organisation, in consultation with business stakeholders, to elicit value add requirements, acting as an interface with broader IT whilst considering a holistic view of current processes, systems to translate the business needs into SMART/INVEST specification and works with development teams to ensure the end results match the specified business needs.
INVEST: Independent, Negotiable, Valuable, Estimable, Small, and Testable
SMART: Specific, Measurable, Achievable, Realistic, and Timely.