The V-Model

The V-model, or Validation and Verification model, expands on the Waterfall model with the addition of early test planning. Instead of moving down linearly through the software development stages, the V-Model moves down until the coding phase when it pivots and begins to ascend upward to form a “V” shape.

Each development stage has a corresponding testing activity. This allows the team to detect errors in requirement specifications, code, and architecture early in the development of the project. Unfortunately, fixing errors is still difficult and expensive as there is not a clear path for resolving these problems.

The addition of early test planning gives the V-Model a greater chance of success than that of the Waterfall model. However, the V-Model is still linear, making it inflexible.

Like the Waterfall model, a team can only start the next stage when the current stage is complete. This makes adjustments difficult, expensive, and time-intensive.

Therefore, this model is best for short projects with fixed, clearly defined, documented requirements, but it is not ideal for long, complex, or ongoing projects.