Can both Waterfall and Agile development be used at the same time?

Coming from an old school background and learning my trade as a Business Analyst straight after Uni, I remained unconvinced about ‘agile development’ for a long time. I only ever saw the best way of guaranteeing project success was by capturing the requirements up front, creating traceability to more detailed requirements and so on. 

Over the last 9 months, I have been gradually converted to the agile method of software development. I owe a large amount of this renewed thinking to one of my colleagues from the US who shall remain nameless (despite the constant hammering about it), but it was not all his doing. More and more of my clients have been asking about Waterfall v Agile and what this actually means?

Over the course of several engagements recently and learning more about the practical application of Agile for software development, I worked with a client that wanted to use both.

Waterfall and Agile? Argh..or Maybe?

Folly! Was my first thought but when I lifted the lid, I found that there can be a place for both on the same project. Case in point, my client was undertaking the initial requirements analysis using Waterfall but wanted to develop using Agile. So we worked it through…

They captured the Business Objectives (level 1), eliciting the High Level Requirements (level 2) and then decomposing these into Detailed Requirements (level 3) and creating traceability across the three levels. Now came flip time. We decided to create work items (tasks) from the Detailed Requirements and enter these onto the Agile Product Backlog (basically the list of things to develop). From here they prioritised some them into a Sprint (a collection of activities to develop in a set time frame)
 and completed the activities (including some testing) to deliver working code at the end of the Sprint. Rinse and repeat for subsequent Sprints and there you have it, Waterfall and Agile playing nicely together.

So far, as long as you have clear demarcation lines between the two methodologies (i.e. they cannot exist in the same project in the same phase), they can coexist peacefully with traceability maintained.

I will post an update in a few months to see how it all turned out. 

I recommend Kurt Solarte's article on baby steps to Agile and Scott Amber's blog on Disciplined Agile Delivery. These further expand further on Agile concepts.