In the last newsletter we discussed the Agile Development Processes, and the implications for product managers. In this newsletter we look at the process that the majority of product teams still follow, which is known as the “Waterfall” process.

Even though the Waterfall development process is more than 30 years old, and even though it is often cursed by engineers and product managers alike, it is still by far the most common process used to create software products.




The conventional waterfall process is extremely simple in concept:

1) Phased Development – the model is that the software progresses through a well-defined series of phases beginning with a written description of the requirements, into first high-level architectural design, and then to low-level detailed design, then to code, then testing, and finally deployment.

2) Phase Review – each phase ends with a review of the deliverables from that phase, followed by sign-off and an explicit transition to the next phase.




- 管理层欣赏该过程的(感知)可预测性。虽然不常见,但甚至是甚至是大型和复杂的软件项目的相当准确的时间表。然而,这假设您完全准确地了解要求和技术,并且不会发生变化。通过迭代方法,您并不真正知道需要多少迭代,这可能会对管理令人不安。

- 整个过程中有可交付成果。通过了解思考和彻底的文档和设计图,许多人(管理者,客户/客户和客户,甚至许多工程师)都是放心的。It helps these people to gauge progress towards the end, and also helps them feel better about the level of thinking that has gone into the project (even though there is no way to test whether or not the confidence is justified because unlike software you can’t execute paper documents). Many people make the mistake of feeling unjustifiably reassured by impressive specifications and documents.



- PM问题:验证发生得太迟了


The product manager must ensure that prior to moving into the design and implementation phases, the product must be prototyped and tested on actual target users, so that the specification that is eventually provided to the product development organization is describing a product that has been successfully validated with the target audience.

Likewise, if there are major technical risks, these too should be explored and feasibility questions resolved (by the engineering organization) prior to beginning the actual architectural design and implementation. Before proceeding, the team needs to know that the product specification is something that can be successfully delivered.

- PM问题:变化是昂贵和破坏性的



– PM Issue: Responding to the Market

This approach has a relatively high overhead in terms of documentation and process for moving through the phases. One consequence of this is that it can take considerable time to make even relatively small changes to the software.

This puts additional pressure on the product manager to ensure that they are providing a validated specification for a successful product in the first place, but it also means that the product manager will need to work with the product team to make course corrections after release as quickly as possible.



In many ways, the Waterfall process represents an idealistic but naïve view of the software development process, where people are able to anticipate the key issues and fully understand the requirements. When this is the case — usually for very small projects — this approach can provide a reasonable path to a quality implementation.

Unfortunately, this is rarely the case with product software. In practice, the consequence is that the product ships later than planned due to changes, and then expensive, time-consuming follow-on releases are required in order to correct issues once real users have a chance to see and use the actual software.


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