June 23, 2016


Waterfall and Agile: Parallel Worlds

‘Legacy IT’ versus ‘modern IT’ seems to be a never-ending debate. And, it’s not the only on-going discussion on global forums. Parallel dialogues on legacy SDLC (System Development Life Cycle) and modern SDLC are equally widespread. In this article, we’ll highlight key SDLC concepts and clarify some of the misconceptions related to the debates around SDLC.

We broadly divide the SDLC into two categories - Waterfall and Agile. Each category has its own variations and subcategories. V Waterfall and CMM are popular waterfall variations while Scrum, Iterative, RUP and DevOps are some of the widely known subcategories of Agile SDLC. There are others apart from these.

This article explains both the similarities and the differences between these two broad categories.

The two important elements which are present in both the methodologies are:

  1. Project management that deals with planning, scope, timeline, and cost.
  2. Core SDLC activities such as design, code, test and validate.

But the approaches adopted in the two categories towards these two elements are completely different.

Let us examine how these two methodologies differ in these aspects.

Project Management

Project management controls three different, but well-connected, aspects of the project—budget, timeline, and deliverables. Controlling these elements independently is not possible. Project management techniques and the roles ascribed within the project are entirely different in these two methodologies.

In agile development, scope cannot be fixed, and thus we fix the schedule. Agile involves constant collaboration and the customer is part of the agile team.

In agile methodology, governance is embedded at every stage of the cycle, and the emphasis on detailed documentation is highly diluted. A working software with basic documentation substitutes several governance artifacts. It is therefore suitable for smaller project where requirements are evolving and changes are common throughout the project.

Waterfall on the other hand has a comprehensive governance and risk management focus. Throughout the project cycle, it emphasizes on the detailed documentation such as Project Charter Preliminary Scope, Business Case/Feasibility Study, Project Plan WBS, Change Control Plan, Risk Management Plan, Risk Register/Issue Log, Action Item list, Resource management Plan, Project Schedule, Project Status Report, Responsibility matrix, Defect database, Defect tracking, Lesson Learned, and so on. It is thus suitable for large projects with clear requirements where changes are uncommon.

Core SDLC Activities

Regardless of the kind of methodology, there’ll always be core activities such as design, code, test, and validate among others present in every methodology. The key difference is how these activities are sequenced (refer Figure 1 & Figure 2).

The Co-existence of Waterfall and Agile

The emergence of agile does not imply the irrelevance of waterfall. As we learn above, both methodologies have their own areas of applicability, and therefore both the methodologies will remain in use.

HCL GBP Implementation

HCL GBP release management was originally designed for waterfall model of SDLC on ServiceNow Release Management module. Its data model has hierarchical structure with hierarchy of product, master release, child feature and task. Lifecycle tracking of release (master and child) and feature can be done individually for developing detailed governance reports. Other features include:

  • Ability to size the release with respect to number of features and arrange tasks in each release.
  • Ability to add and remove feature in later stages of the lifecycle.
  • Ability to transfer feature(s) from one release to another.
  • Inclusion of a task management platform.
  • Presence of system of record and system of collaboration.
  • Integration with change control.

Since GBP RM is built to manage the core activities of SDLC, it can be used for Bi-Modal RM as well. Think of GBP as the conveyor belt for both Waterfall and Agile release management process orchestration. When you have a large release that uses both types of methodologies, you can define Waterfall release as well as Agile release for the same product at the same time, and simultaneously run two processes in parallel on the same conveyer belt.

HCL also offers GBP Agile RM that is built on the Scrum module—think of it as the second conveyer belt. GBP Agile RM also has a similar hierarchical structure as GBP RM, with the hierarchy taxonomy based on Scrum terminology—Agile Release, Scrum, Story and Task. This is a separately licensed module as compared to GBM RM that is included in ITSM license pricing.