Agile vs Waterfall: What It Means for Business Analysts

May 20, 2026

Agile versus Waterfall is one of the most common business analyst interview questions, and for good reason — the methodology fundamentally changes how a BA works day to day. Here is what actually differs.

Waterfall: plan everything upfront In Waterfall, requirements are gathered and documented in full before development begins. The BA produces detailed BRDs and FRDs, gets sign-off, and hands them to developers. Phases happen in sequence: requirements, design, build, test, release.

The BA role in Waterfall is heavy on documentation and upfront analysis. Your deliverables are comprehensive and formal. This suits projects with fixed scope, regulatory requirements, or where the cost of change is very high.

Agile: discover as you build In Agile, requirements emerge and evolve across short iterations called sprints. Instead of one large BRD, the BA writes user stories with acceptance criteria, refines a backlog, and works closely with the team every day.

The BA role in Agile is heavy on collaboration and continuous refinement. You write less formal documentation but communicate far more frequently. This suits projects where requirements are uncertain or the market moves quickly.

Key differences for the BA Documentation: Waterfall favours comprehensive documents; Agile favours just-enough user stories. Timing: Waterfall front-loads analysis; Agile spreads it across the project. Change: Waterfall resists change after sign-off; Agile expects and welcomes it. Stakeholder contact: occasional and formal in Waterfall; constant and informal in Agile.

The honest truth: most teams are hybrid In practice, many organisations run a blend — an upfront BRD for the business case and budget approval, then Agile delivery for the build. A strong BA adapts their toolkit to the project rather than insisting on one religion. Knowing when to write a formal document and when a user story will do is itself a senior skill.

Whichever method you use, our template kits include both formal BRDs and Agile user story templates.