3 Interview Qs About the Waterfall Development Model

Sometimes an old-fashioned approach is the most effective. Take the Waterfall model, for instance. Although the process of sequential software development has been around since 1970, it’s more effective than newcomer Agile… under the right circumstances.

Interview Qs“Waterfall is still a sound methodology,” said Dennis Kayser, CEO of Forecast.it, a project solutions firm based in Copenhagen. “PMs really need to know several methodologies and when to use them, because Waterfall might produce better results depending on the nature of the project.”

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Kayser believes these interview questions will offer good insight into whether a PM knows when to use the Waterfall model:

When would you choose a sequential process like Waterfall over Agile?

  • What Most People Say: “Waterfall is an old fashioned model that is better suited for construction projects than software development. Agile is the way to go, since it creates a Minimum Viable Product (MVP) very quickly and time is money.”
  • What You Should Say: “It depends on the nature of the project. Waterfall is superior if the requirements are clear from the outset and stable. Waterfall also tends to be more effective when a team has successfully completed similar projects, there are heavy dependencies on other projects, and stakeholders aren’t readily available. On the other hand, Agile is better suited for smaller independent projects where creating an MVP is paramount.”
  • Why You Should Say It: A skilled PM knows when to employ each model. Waterfall can be an excellent model, especially when members of the development team come and go throughout the course of the project and stakeholders can’t provide timely feedback on deliverables. If multiple systems, components and software packages need to be integrated and launched at the same time, the situation calls for an early design, which is ideal for a sequential approach. Waterfall requires more up-front planning, but that doesn’t mean that things can’t change as the project progresses. If a resource leaves a Waterfall project, a new resource can easily pick up the work, which often is not the case with Agile. Also, timetables and budgets are more easily and accurately predicted under the Waterfall method.

Does Waterfall or Agile typically create higher overhead?

  • What Most People Say: “Agile creates the least amount of overhead because it involves rapid development and prototyping as you go along. And you don’t have to generate change requests because you can adapt the requirements on-the-fly. Conversely, change requests are cumbersome under Waterfall. They require multiple approvals, take more time and drive up overhead.”
  • What You Should Say: “Depending on the project, Agile can generate much higher overhead. This is due to the flexible nature of Agile where project priorities are re-evaluated on an ongoing basis, and code may be rewritten over and over again, resulting in a piecemeal system. Longer sprints are one of the best ways to control overhead in Agile projects. In a sequential model, code is rarely rewritten. In fact, if the right processes are in place, Waterfall is actually pretty lightweight and is certainly more cost-effective.”
  • Why You Should Say It: If the requirements are stable from the outset, change requests are actually not that common in Waterfall, which reduces overhead. And if the PM is skilled and establishes a proper change request process, it’s not that hard to change things in a Waterfall model. It’s important to understand that heavy interaction between designers, developers and integrators takes a lot of time in Agile. PMs tend to underestimate the cost of communicating and interacting with prototypes, as well as the impact of delays when stakeholders are hard to reach; meetings are postponed and decisions linger.

Why is Waterfall advantageous when a project requires specialized staff and skills that are in short supply?

  • What Most People Say: “Because Waterfall emphasizes planning, PMs have a chance to look ahead and schedule resources when they’re available.”
  • What You Should Say: “Waterfall maximizes resources in several ways. First, PMs can anticipate and schedule designers and architects when they’re available. Second, because documentation occurs as you go along, specialists can work on other projects when they aren’t needed, which increases utilization. It is much harder to maximize resources in an Agile project, where specifications, timetables and priorities are always changing.”
  • Why You Should Say It:  Using specialists efficiently in short bursts is much better than having them wait around, especially when you may be paying top dollar, travel and per diem costs for globe-trotting professionals. Plus, Waterfall’s emphasis on documentation lets another specialist step in if the original resource is unavailable. On the other hand, a key resource dropping out can be catastrophic for an Agile project.

“PMs have the ability to condense time frames under the Waterfall model, which makes it easier to schedule and allocate resources,” Kayser says. “It’s the better model when professionals with specialized skills are in short supply.”

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2 Responses to “3 Interview Qs About the Waterfall Development Model”

  1. CoderDude

    Waterfall is great IF your PMs/stakeholders can get their s*** together to give you a reasonably comprehensive set of specifications before work starts. That’s a BIG if. In my experience, the stakeholders say they want one thing, really want another, and neither of those are what they need. So, while Agile may have more overhead (and certainly more meetings), it tolerates clueless business interests better. Chances are, Waterfall or Agile, that you will be reinventing wheels during the entire process. Agile is better suited for this, because it plans for it.

  2. @Coderdude

    I agree, to an extent, and that’s also the argument. There are though several instances where a waterfall approach can be better suited and should be chosen over agile.

    I think the most important thing to acknowledge is that the method should be chosen based on the type of the project not based on religious views of methodology.

    In the case, that you refer to, where you’re building software, with a contained team, towards business stakeholders that are not completely clear on what they want, then yes agile will be the better approach.