Although there are many reasons for Waterfall Failure or Waterfall ‘Leaks’, here are some common causes:
Requirements & Scope Control
Requirements tend to be unclear, lack agreement, lack priority, can be contradictory, ambiguous, and imprecise. With that said, Waterfall assumes a detailed set of requirements will be 100% accurate at the beginning and locked for the duration of the project. Changes to requirements are bad and Waterfall tries to minimize once the plan is created.
Planning (schedules & budgets)
Schedules and budgets can be based on insufficient data, missing items, insufficient details, and poor estimates. Waterfall assumes the initial estimates are locked and accurate. Frequently dates and budget are decided well before even project engineers had a chance to provide their own input on estimates. These same team members are then forced into long spanning timelines they don’t agree with. This can also lead to overly cautious PMs who end up in ‘analysis paralyses’ during the planning phase in an attempt to perfect estimates which can delay the start of the project.
Another common reason for failure is poor communication and stakeholder engagement. This also causes lack of clarity and trust. Waterfall assumes the PM should plan all the work or tasks (i.e. planning from the center) and the project team must execute the tasks they are assigned. There is no sense of ownership from the team’s perspective.
Customer Value (and quality):
Typically, Waterfall does not provide any value back to the customer until the very end after all other phases. All requirements are locked together as they journey through all the waterfall phases only to realize that what they wanted a year ago is already obsolete and needs changing. Waiting to do the testing until the end of the project risks finding out a major issue right before deployment which will cause the project dates to slide and be over budget. A common waterfall solution to this is to reduce testing effort to ‘keep the dates’ and turn over a poor quality system into production. Read more