Waterfall vs Agile: Choosing the Right Development Model

Waterfall Model

The Waterfall model is a traditional development approach commonly seen in B2B systems such as ERP, MES, WMS, CRM, OA, and IBMS, and it remains popular for large or outsourced projects.

The diagram above highlights the clear strengths and weaknesses of the Waterfall model.

Advantages

Clear phases: planning, development, and deployment are distinctly separated.

Sequential timing: each phase must follow the previous one strictly.

Interlocking deliverables: output from one phase is required before moving to the next.

Black‑box approach: each phase has its own roles and responsibilities, allowing participants to focus solely on their tasks.

Disadvantages

Requirement isolation: team members only see their own slice of the project, leading to uneven understanding of customer needs.

High change cost: returning to a previous phase is costly and often met with resistance.

Creativity constraints: heavy documentation can stifle innovative thinking.

Long cycle: extensive time spent on requirements and design can extend the overall timeline to six months or more, making it suitable only for large, stable‑requirement projects.

Summary

The Waterfall model emphasizes milestones, documentation, strict division of labor, and planning, but it suffers from sluggishness, heaviness, and slow response to change.

Agile Model

Development Background

Agile development rose with the internet era, fitting the fast‑moving B2C market exemplified by products like QQ and WeChat, where core features are delivered first and additional functions follow.

Internet products follow Lei Jun’s four‑word mantra: focus, excellence, reputation, speed.

Only focus can concentrate energy and spark breakthroughs.

Only excellence can outpace competition.

Reputation outweighs awards.

Speed is the ultimate weapon.

Agile aligns better with these needs; using Waterfall alone would cause delays. Some teams even adopt a crowd‑sourced “PPT‑crowdfunding” approach to validate ideas before development, avoiding wasted effort.

What Is Scrum?

Scrum, named after a rugby term meaning “to contest the ball,” represents a high‑energy, collaborative development process. Scrum and XP are concrete implementations of Agile principles; this article focuses on Scrum.

Scrum defines three roles:

Product Owner: Provides the overall product backlog, defines boundaries, prioritizes features, sets delivery dates, and can reject work that does not meet expectations.

Development Team: Self‑manages, delivers quickly, and must communicate proactively.

Scrum Master (Process Manager): Removes obstacles between business and development, acting as glue; may also reject unreasonable change requests.

Scrum works only when roles are filled, responsibilities are clear, and communication is smooth; otherwise efficiency drops.

The fundamental difference between Scrum and Waterfall is that Scrum is people‑centric while Waterfall is document‑centric.

Scrum Process Diagram

First, create a product backlog managed by the Product Owner.

The Development Team estimates and plans the work.

From the backlog, a story is selected for the upcoming sprint (1–4 weeks) and broken down into a minimal viable product.

Each story is further split into tasks that can be completed within two days.

During the sprint, teams use a “planning poker” technique to estimate effort and reach consensus.

Daily stand‑up meetings (≈15 minutes) where each member answers three questions: what was done yesterday, what will be done today, and what blockers exist.

After each stand‑up, the sprint burndown chart is updated on the board.

Daily integration: A build that compiles and runs every day, often supported by CI/CD tools.

When a story (the sprint goal) is completed, a demo meeting is held with the Product Owner and stakeholders to showcase the increment.

Finally, a retrospective meeting is conducted where every participant shares feedback and improvement ideas for the next sprint.

When followed faithfully, Scrum provides a highly efficient development workflow.

Waterfall vs Agile

Comparison Overview

Both models have clear boundaries; teams must understand where each excels and reach consensus to avoid serious issues.

Key problems arise when consensus is lacking:

Misguided leadership: Managers who over‑emphasize documentation can stall progress, leaving developers idle.

Low team efficiency: Strict hand‑offs cause bottlenecks—design waits for requirements, developers wait for designs, testers wait for code—leading to delays and potential conflict.

Takeaways

Waterfall and Agile are not mutually exclusive; they complement each other. Large features may still follow a mini‑waterfall within an Agile sprint. Small startups often need flexible roles, while strict Waterfall can cripple a lean team.

Balancing the two requires experienced managers who can judge when to apply planning versus rapid iteration, ensuring both delivery speed and adaptability.

Without shared understanding of the development model, team efficiency suffers, yet many teams still work without formal training.