Tag Archives: JIT

Two dimensions: Just in time and Envisioning

A paradox?

In the previous post (JIT – Just in time and Software Development) I have discussed the importance of JIT approaches in Agile Development. In fact, JIT mean adaptive and that it’s “synonym” with Agile. Anyway, no human endeavor can be 100% adaptive. There is also another dimension, related to need of envisioning. Software development it is, by its nature, a “design” activity, where design, also by its nature, it is an envisioning kind of activity. We have an apparent paradox here: Software Development it is both JIT and envisioning by its nature.  In fact it is not a paradox, because design-envision and JIT-adaptive could be unified when we tailor the process in context (see also Adaptive Design)

Paradox: by its nature, software development suppose both JIT and Envisioning

Why we need envisioning – Agile practices

We need envisioning for any human endeavor, but here are some needs related to the software development:

  • A software solution – design and architecture tell us that we have a valid solution, we are ready to plan the work and then ready start that work.
  • A software release – (in Agile: rather small releases) must be delivered in time for the target business needs and that need envisioning: for requirements, envisioning  for solution (design and architecture), costs, time, resources and other plan elements.
  • Lean! – looking ahead could

More concrete, let’s see how the mentioned Agile practices have envisioning as a purpose:

  • XP – Architecture Spikes help to reduce the risks related to solution and also help to estimations. System Metaphor will help everybody to understand the system, even the new people
  • Scrum – Product Backlog it is just an envisioning of incoming work! The backlog refining it is just a clearer envisioning of that work.
  • DAD – We have here a clear support for envisioning a software release by explicitly Scope exploration, Architecture Envisioning and stakeholder’s agreement on the vision about solution delivery.

A very interesting DAD practice it is Look Ahead Modeling, that opportunistically envision some requirements and solutions parts. It is similar with Refining from Scrum, but is clearer about the intent and more effective on dealing with future communication risks. Another improvement that come with DAD, it is the concept of consumable solution: it is a better definition of Done, that will make any envisioning effort more effective.

More (on DAD): the explicit models of the possible development/delivery life-cycles make clearer the used ratio between envisioning and JIT:

  • Agile and Lean life-cycles
  • Continuous-deployment – where the context “force”  a JIT approach
  • Exploratory life-cycle – where the context “force” envisioning

Should be observed that the two approaches must be balanced and in the extreme cases we must be very careful with applying the elements of other dimension:

  • Continuous deployment – it is a permanent JIT, but is not only JIT. Product Backlog and Look Ahead Modeling will be here extremely useful to envision/refine the incoming work and make continues deployment more effective.
  • New product on the market – seems to be 100% envisioning, but that suppose very high risks and break the rules of managing high complexity. Using the DAD Exploratory Life-Cycle, we will introduce more feedback loops and we will have in fact a sequence of smaller releases, that mean we balance somehow to the JIT side.

Two dimensions: Just in time and Envisioning

Distinct dimensions will always coexist, we cannot choose between them, but only adjust to to the proper balance . Let’s re-formulate some rules of JIT together with the ones of envisioning:

 Do not make guesses about incertitude.

You cannot “compute” something that is too complex.

Context introduces incertitude and complexity, but also some constraints for envisioning and visibility. According to the context, should be used a valid, balanced, adapted combination of envisioning and JIT.

Increase visibility (“readiness”) by removing the incertitude and complexity on various levels of incoming work: product, release/project, iteration and further.

Each transition from incoming work to the work in progress suppose a proper degree of readiness: product to release, release backlog to iteration backlog, iteration backlog to tasks.

The “Ready” to work state introduced by Scrum, it is in fact the effect of envisioning (where Scrum use the term /practice of “refining”) of the incoming work, but should be re-think in order to be applied on more levels, not only for the iteration start. A definition of “Ready” for starting the Construction in a release/project could be found in DAD and it is represented by the elements of the Inception part, responsible with envisioning. The “Proven architecture” milestone it is a validation of this “Ready” for (continue) Construction.

In a 3D space, we cannot choose to live in 1D or 2D

JIT – Just in time and Software Development

(See also Part 2 – Two dimensions: Just in time and Envisioning)

JIT – solution for incertitude and complexity

Driven forces that introduces JIT Life-cycle in software development

  • Business side: often changes – it is too complex to perform (too much) ahead requirements gathering
  • Development side: software solutions are mostly design (instead of production) it is too complex to manage big chunks

As a consequence of the degree of incertitude and complexity for both requirements and solution, the life-cycle (planning) that suit better will have a JIT model. Agile development has adopted from the start such approach in its principles and practices: often and small releases, iterative development.

JIT approach it is a solution for dealing with incertitude and complexity.

JIT approach it is a solution for dealing with incertitude and complexity. It is similar with the mathematical approach to solve non-linear problems: feedback based approaches (control theory).  The main issue is that you cannot compute (in mathematics) something that is too complex. In software development that mean you cannot envision too much requirements, solution and plan because of incertitude and complexity.

You cannot “compute” something that is too complex

Agile is one of the development approaches that already use JIT for more aspects. We can observe that XP that use “small releases” approach, use also “simple design” principle/practice – they do not want to make guesses about possible solutions aspects, required by possible future change request.

Let reformulate some JIT aspects:

  • do not make guesses about incertitude (what is difficult of impossible to clarify)
  • do not try to “compute” too complex problems

Do not make guesses about incertitude

If these principles are not follow, we will have the same problems as in mathematics: huge deviations of the solution for small changes in the inputs. Translating to the software development that mean huge waste.

JIT and Agile

Some Agile principles and practices that already use JIT approach:

  • Responding to change over following a plan” (Agile Manifesto – value)
  • Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.” (Agile Manifesto – principle)
  • Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale” (Agile Manifesto – principle)
  • “Business people and developers must work together daily throughout the project.” (Agile Manifesto – principle)
  • Make frequent small releases.” (XP rule)
  • No functionality is added early.” (XP rule)
  • Simple design (XP Practice)
  • Model Storming (Agile Modeling / DAD – Disciplined Agile Delivery practice)
  • Document late, document continuously (Agile Modeling / DAD practice)
  • Active stakeholder participation (Agile Modeling / DAD practice)
  • Just Barely Good Enough (Agile Modeling / DAD practice)
  • Explicit support for JIT based life-cycles: Agile, Lean, Exploratory  (DAD – Disciplined Agile Delivery)
  • Inspect and Adapt (Scrum principle)

JIT – main difference versus manufacturing

We need to deal with the main difference versus manufacturing: JIT design versus JIT production. In manufacturing we repeat the solution (design) from the last life-cycle and in software development we need to find a new solution for the newer requirements (metaphor: the market request every time car with a new design). The major problem here is to integrate the previous simple design with the current simple design (there are not just additive). We need that:

  • The existent design must be easy to extend
  • Integration of “next” design must be quick, easy and clean

I have described a solution for this problem in a previous post, a solution that re-arrange some already know thinks from XP and Refactoring (as it was defined in the Martin Fowler book) –  an Adaptive Design based on this rules:

  • Use simple and clean design and then adapt for new changes (example of adapt “tool”: refactoring)
  • Use design practices that increase the adaptability (Refactoring, TDD, Clean Code, Clean Architecture)

JIT production from manufacturing it is based on responsiveness of a highly automated production. JIT design from software development it is more difficult to be automated, but we need to find that solution for responsiveness – it is mandatory to have an Adaptive Design.

Summary

  • JIT approach it is a solution for incertitude and complexity, that it is validated also in mathematics
  • Software development main problems are related to incertitude and complexity, that mean JIT approach could be useful in various ways
  • JIT rules: do not make guesses about incertitude, do not try to “compute” what it is too complex
  • There are many Agile values, principles and practice that are based on JIT approach
  • JIT Design require an Adaptive Design
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