There are 9 pillars to Business Analysis. These pillars are used with the inquiry model to elaborate and elicit the business solution. There is a lot of cross-over between the pillars, but they support a solid business solution.

Context Modeling - context diagram, market analysis, competitor benchmarking, customer feedback, product placement in marketplace, focus groups, environmental analysis, SWOT

Scope Modeling - functional decomposition, scope visualization to establish the boundaries of what is to be delivered, prioritization techniques, product roadmaps, story mapping

Process Modeling - process flow diagram, swim-lane, value stream

Interaction Modeling - system to system diagrams, API models, State diagram, activity diagrams, ETL (Extract Transform Load), Business Intelligence

Decision Modeling - Decision tree diagram, decision log, weighted ranking table, decision table, logical decision path. Multiple criteria path.

Data Model - data dictionary, glossary, logical data model, physical data model, Entity Data Relationship Diagram, Data Flow Diagrams

Business Rules - self-imposed constraints, external constraints by government or regulatory, you will find them in a data model, decision models, and process models

Technical Modeling - entity, class and object modeling, configuration modeling, nonfunctional or environmental requirements to the next level, security, platform models, unique system setups,

Interface Modeling - Prototyping, wireframing, report mockups, UX, storyboarding.

If you covered all of these 9 pillars thoroughly, that could potentially be over 5,000 details or requirements to answer a single question or requirement. The pillars allow you to see how a requirement would fit into your organization from many different perspectives. The better constructed and detailed the pillars are, the stronger the requirement.