All projects across industries follow a life cycle approach. Often I have seen there are so many questions in mind for many PMP® aspirants on different types of life cycles. Why do we really need anything other than predictive life cycle, which goes quite sequential and looks perfect? What are these new buzz words, i.e. iterative & adaptive? What these new life cycles do differently? Let’s clarify all these doubts today and be ready to answer all the questions revolving around it.

First of all we shall look at what is a Predictive Life Cycle

“Predictive life cycles are ones in which the project scope, and the time and cost required to deliver that scope, are determined as early in the project life cycle as practically possible”

PMBOK6

  • This life cycle is known as plan driven life cycle
  • This life cycle is where requirements are defined early and not expected to change
  • With this, project phases proceed through sequential or overlapping mode
  • Change during the later stages of projects cause huge cost over runs
  • The end result is delivered only at the completion of all the phases
  • E.g. a yearlong project will have Planning, Analysis, Design, Code, testing phases one by one and then the final result is delivered over a year

Now we are clear how this most common life cycle work. Let’s go to the next step. What is an iterative life cycle?

“Iterative and incremental life cycles are ones in which project phases (also called iterations) intentionally repeat one or more project activities as the project team’s understanding of the product increases. Iterations develop the product through a series of repeated cycles, while increments successively add to the functionality of the product”

  • This life cycle is used for projects where change in the scope need to be managed
  • In this life cycle plan is detailed for coming iterations and high level vision is created for rest
  • With this, project phases proceed through sequential or overlapping mode in every iteration
  • Change during the project is naturally handled in upcoming iterations
  • The end result is delivered at the end of each iteration
  • E.g. a yearlong project will have 3 months iterations and each iteration will execute Planning, Analysis, Design, Code, testing phases and deliver the result at the end of the iteration

Ok, we now understand these two bits, i.e. Predictive and Iterative and this is pretty much everything one can do, then what this adaptive life cycle is

“Adaptive life cycles (also known as change-driven or agile methods) are intended to respond to high levels of change and ongoing stakeholder involvement. Adaptive methods are also iterative and incremental, but differ in that iterations are very rapid (usually with duration of 2 to 4 weeks) and are fixed in time and cost”

  • This life cycle is used for projects where rapid changes are expected and scope is not possible to define up front
  • In this life cycle scope is decomposed into a set of requirements known as product backlog and getting picked as per priority from the set in every iteration
  • With this, project phases proceed through sequential or overlapping mode in every iteration
  • Change during the project is naturally handled in rapid iterations
  • The end result is delivered at the end of each 2-4 week iteration
  • E.g. a yearlong project will have multiple 2-4 week iteration and each iteration will execute Planning, Analysis, Design, Code, testing phases and deliver the result at the end of the iteration

Iterative and adaptive Life Cycle

This is how the world is moving, especially the software industry. The transition is happening from predictive to iterative to adaptive i.e.an agile way of working. PMBOK® Guide Sixth Edition also included flavors of Agile in it in the form of adaptive life cycle. Ever changing needs of customers and inability to foresee the market and predict the behavior is the key driver to make this transition.

Let’s quickly recap the similarities and differences of all these three types of life cycles

ParticularPredictiveIterativeAdaptive
Stages/ PhasesCan happen sequentially or overlapCan happen sequentially or overlapCan happen sequentially or overlap
Stages/PhasesPlanning/ Analysis/ Design / Code/ testing all takes placePlanning/ Analysis/ Design/ Code/ testing all takes placePlanning/ Analysis/ Design/ Code/ testing all takes place
ScopeDefined upfront at the beginningDefined for upcoming iteration and high level vision for the restScope is set in the form of features from which features are picked for the current iteration
ChangeAt initial phases/stages can be accommodated. Cost overruns as late it comes up during project LifecycleTaken care with less cost impact during the planning of the next iterationTaken care even more rapid changes every 2-4 weeks with less cost impact during planning of next iteration
RiskThe risk of change/ feedback is huge at later stages/ phasesThe risk of change/ feedback is less as iterations reduce it naturallyThe risk of change/ feedback is least as iterations are too small and reduces it naturally
Customer FeedbackCustomer feedback is received at the end of the project only and customer involvement is more at the beginning and endCustomer feedback is received at the end of each iteration with which customers are involved multiple times during the projectCustomer feedback is received at the end of each rapid iteration. Customers are involved/engaged continuously
ComplexityUsed for projects where the product to be delivered is well understood and complexities are not there to handleUsed where a change in objectives/ scope need to be managed and complexity reduction is required as the project progressesUsed in a rapidly changing environment, where scope/ requirements are difficult to define in advance and possible to define small increments
Delivery/ValueDelivery happens at the end only once and the customer gets value at the endDelivery happens at the end of each iteration and customer gets value early in the projectDelivery happens very rapidly after each 2-4 weeks and customer get the value delivered very frequently

 

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