<I wrote this article first for ProjectManagement.com here as part of their Requirements series>

Agile approaches are often used on projects where the end goals are not fully known or may change during the life of the project. This seems unusual to my engineering PM friends who manage the fabrication of facilities. To them, not knowing what it is you are supposed to be building or letting things change along the way is a sign of poor scope definition, requirements gathering, and change control. I hear quips from them along the lines of: “You guys need some rigor and decent specifications, maybe then you could build IT systems that work and don’t go over budget!”

They are right of course, for their domain of defined repeatable projects; first establishing a well formed scope definition and complete specification is the way to go. However, many IT projects are not defined, repeatable endeavors, but instead design explorations into unchartered territory for that organization. The mix of technology has not been used that way before. Sponsors have a vision of the end state, but not a lot of specific detail. No matter how much upfront work is done there seems a host of unknown issues that surface during the journey to the destination. Build/ feedback cycles with adaptive plans and progressive elaboration of requirements is the way to deal with these inevitable uncertainties.

These intangible, unprecedented, emergent, evolving characteristics of IT projects are difficult to explain, but need to be understood. They impact how we plan and execute today’s knowledge worker projects as well as how we should manage requirements. When the specifications are clear such as “A kitchen reno with new counter tops and appliances” then simple, signed off requirements can work well. Yet when things are more vague such as “A winter vacation to someplace warm” remaining flexible to changes and new ideas can be valuable.

Let’s look at some of the differences between plan driven, traditional practices for requirements management and those used in agile methods:

Learning and applying traditional methods of requirements management is easy, it is akin to a shopping list approach. We ask questions like “Did you get milk?”, “Did you get the bread?”, “What else do we need?” Changes may be declined or accommodated. “Billy wants some chocolate!” too bad, tell him he can’t have any, or “Oh, I remember we need light bulbs!” We can then ask do we have enough money for light bulbs, do we have time to go find them, etc. It is all pretty much second nature.

Agile requirements management on the other hand is less intuitive. The constant reprioritization, comparison of new ideas with remaining features, and focus on business value has more balls in the air. Like packing a backpack for a multi day camping trip we are always weighing up the benefit verses the size / weight penalty of bringing something along while keeping an eye on an ever changing weather forecast. There is more re-evaluation, more substitutions, more “Do you really need it?” type questions.

Traditional requirements management has a more satisfying progression of closure – Feature A is in the signed off spec, so we are doing it! This is like saying it was on the shopping list so we will buy it. The fact that it may then sit in a cupboard and never be used is a separate discussion. Agile requirements management lacks this reassuring closure since all remaining items are up for reprioritization or substitution until the completion of the project. Our shopping list is being changed as we walk around the store and that makes some people uncomfortable. However, fewer items should go unused.

In the end it comes down to trading off certainty against flexibility and value optimization within your purchasing decision. If you know you want a vacation at the Hotel Del Coronado in San Diego and that ticks all your boxes then you can lock down the requirements early, book it and be done with it. If you are not sure if the twins will be joining you for a vacation and are looking for the best value 4 star hotel; you will want to keep your options open longer and have some flexibility to best satisfy your purchasing needs.