Atern’s second principle is “Deliver on Time”. What, I hear you ask, is different about that? Every project in history has aimed to deliver on time. And a lot have failed.
True, but what makes Atern different is that it is specifically designed to meet this objective, provided you follow the rules.
Rule 1) Define the breadth of your requirements without going into too much detail. See my previous post on Story mapping for a great way to do this.
Rule 2) Estimate the relative size and complexity of each requirement (user story if that’s what you’re using) and derive the duration during the Foundations phase (see Principle 5 when I get there). This technique is best understood by reading Mike Cohn’s seminal book “Agile Estimating and Planning”.
Rule 3) Utilise MoSCoW prioritisation.
MoSCoW stands for Must, Should, Could and Won’t Have (this time). And if you are ruthless about allocating as Must Have only those stories without which you would delay the implementation, and ensure that the total effort in the Musts is no more than 60%, you can guarantee to deliver at least those on time because you have 40% of your effort allocated to non-essentials. This is feature-contingency and it allows you to deliver the Must Have’s on time. Of course, 20% or so of those non-essentials are quite important Should Have requirements, but if push comes to shove, they could wait until the next release. The remaining 20% – the Could Haves – are the nice-to-have features, the “bells and whistles” that are the first to be sacrificed when a new requirement comes in or things take longer than expected.
The iron triangle of time, cost and scope must have at least one edge that is flexible, or the project is almost certain to fail. In a waterfall project the scope (the specification) is fixed and time and cost extend to meet it. In Atern, time and cost are fixed early on and the scope is flexible, based on business priority. Make sure it is the business who are making the priority decisions.
When was the last time you delivered a project on time and delighted your customer in the process?