f3yourmind

Scrum people like to use points for estimating and measuring velocity.  I won’t go into detail about how points work and how to play those poker estimation games.  Just search around and you will find a ton of stuff.  So, back to this points stuff.  I have a divided relationship with the humble point.  I like it when a team switches to using points for the first time, because it gives them a chance to think a little bit deeper about what they want to do.  I don’t like it when we start inventing rules around points (and you can lump guidelines and best practices into the rules pot too).  When the rules appear, the thinking disappears.

In every team trying Scrum, there is bound to be a rule about points.  I dare you to put up a hand and say you have none.  These rules are things like “We can’t take anything over 13 points into a sprint”, “Our epics are 100 points”, “The login screen is our baseline of 3 points”, “Anything over 40 points must be broken down”.  So, I double dare you

I have different view of the humble point. A point may seem like a one dimensional thing, but it has a some facets built into it.  One facet is the “amount of effort to build something”.  Another facet is “amount of ignorance” and this has an inverse – “amount of shared knowledge”.  Sometimes I find it useful to make a judgement based on what I don’t know as opposed to what I do know.  Regardless of whether I choose to view the cup as half full or half empty, I cannot estimate effort to build something based upon what I don’t know.  So, effort tends to track the amount of knowledge, not ignorance.  As knowledge increases, my ignorance decreases and each point starts representing more and more of pure effort.

However, if I am in a state of complete ignorance, then it is completely impossible for me to make any judgement on effort to build.  I’d be simply speculating.  What I can do, though, is create a time box to explore the unknown so that I can start moving out of my state of ignorance.  This is also an estimate and I am not making an excuse for non-delivery either.  I need to understand some things and also show my understanding in some code.  Yes, the code that I produce may not have a visible user interface or some other convenient demo-friendly stuff, but I need to carefully plan my sprint review to express my understanding.

It’s all about gaining a SHARED understanding. This understanding is body of knowledge that I have learned which I need to confirm with others.  This act of confirmation can happen in several ways.  I can have a conversation and explain what I understand, I can draw a blocks and lines picture, or show a spreadsheet, and so on.  Regardless of the method of communication, I still use the opportunity of discovery to express my understanding in code as tests.  Another powerful way of expressing my understanding is to write out a story and a few scenarios.  Using BDD style grammar can be a great way of concisely expressing some things, that can be easily shared.  Yes, you heard me correctly – as a developer, I write the stories and scenarios.  When I am given a story and scenario by someone and asked to estimate, then I am attempting to estimate based on  another person’s expression of their understanding and my assumed understanding.

In a recent discussion with Jimmy Nilsson, he said that he prefered to call scenarios “examples”.  That really resonated with me.  I also do a lot of discovery by example, and then gradually introduce more a more into the examples, as I get more and more confident of my knowledge.

How do I know how much I don’t know? That’s a tough question.  What I do comes straight out of my TDD habits.  I create a list of questions – my test list.  For some questions, I will know the answer easily, some not all, and some are debatable.  The more that I can answer, the better I can estimate effort.  I can then turn the questions that I can answer into statements of fact.  The more facts I have, the less ignorant I am.

Recently, I worked with a team that wanted to get TDD going, and the most significant change that I introduced was in backlog grooming and sprint planning.  During these two ceremonies, we (as a team) threw questions madly at a requirement, regardless of whether we knew the answer or not.  We then worked through the questions (as a team) to establish how much we could answer.  The trend that emerged was that the original estimates where either half of the new estimate or double of the new estimate.  When they where halved, it was generally because we were able to negotiate some of the unknowns (the ignorant areas) to a future sprint with the product owner.  In some cases, the product owner was equally ignorant, and was reacting to the “business wants the feature” pressure.  When they were doubled, it was so much more was discovered than originally assumed.  At the end of the session, we always asked the meta-question “If we answer all these questions sufficiently, will we be done?”.  I call this style of working “test first backlog grooming” or “test first sprint planning”.

Often I discover more things I don’t know. Annoyingly, this happens in the middle of a sprint, but if it did not happen in that phase of work, then perhaps I was not digging deep enough.  When this happens, I just keep on adding them to my list of questions.  These new questions are raised at any time with others on the team, the customer or with whoever can help me understand a bit more.  Sometimes, it’s put on the table for negotiation to be dealt with at another time.  Nevertheless, standups still seem to be a good time to put new questions on the table, for discussion later.

There are several ripple effects of thinking about points in this manner – this notion of ignorance and shared knowledge gauges.

The first is about the possible shape of your sprint backlog. If you have deep understanding, then it is likely that you will be able to decompose complex problems into simple solutions, that take less effort.  The effect is that low point stories are in greater number in a sprint.

If you are highly ignorant, then the estimation points reflect that and there are more medium to high point stories in the sprint.

Sprint backlog shape with high ignorance

The second is about what you value in a story. You will find less value in the ontology of epics, themes and stories.  It is no longer about size of effort but degree of understanding or ignorance.  Instead, the shape of the product backlog is something that is constantly shifting from high uncertainty (big point numbers) to high certainty (low point numbers).  That’s what test first backlog grooming gives you.

Shape of product backlog - higher knowledge items have smaller points.

The third is about continuous flow that is the nature of discovery.  When you work steadily at reducing your degree of ignorance, then you are steadily answering questions through answers expressed in code, and steadily discovering new questions that need answering.  This process of discovery is one of taking an example based on what you know in this moment and modeling it.  Then expanding that example with one or two more additional twists, and modeling that, and so it goes.

It also touches product ownership and software development. When you work in this way, then explicit estimation of effort becomes less significant.  Moments that have been earmarked as important  points in the life of the product become more significant.  Call them milestones.  These milestones are strategically and tactically defined, and become a dominant part of product ownership.  Software development becomes the act of having long running conversations with the customer.  Those milestones give context for the content of those conversations.  Ultimately, those conversations are then expressed as a set of organised thoughts in code.  If your code is not organised well, then perhaps you also don’t understand the problem or solution or both.

This is a long story for a short message. A high priority is to resolve the tension that exists in an estimation in the form of knowlege/ignorance fighting against effort.  When you release that tension through shared understanding, then you can deal with the tension that exists in the act of creating those significant milestones.  In my opinion, that’s the real wicked problem.

It was really good to be part of a very topical subject at the JCSE Architecture Forum last night.  While these discussion are so valuable, the things that surface can only be glossed over, largely because of time constraints.  I end up feeling a very satisfied and energised but a part of me feels a bit hollow.

So here are some of the things that surfaced at the Forum, and my narrow, unworldly opinion on each (i.e. I’m just trying to fill that hollow feeling).

When we talk about architecture, we need to define what we mean by architecture?

In my talk it was a very simple view of architecture which, thinking back, I should have disclosed very early.  I am now applying from Kent Beck who talks about mutually beneficial relationships.   So I think of architecture as the mutually beneficial relationship between two or more things.  So what is a thing?  It could be  lines code in a method, methods in a class, classes in namespace, namespaces in code base, binaries in an application server, application servers in a cluster, … see where I am going?  Architecture is about creating beneficial relationships, and the 5 things I discussed are based on this view.  If you don’t know anything about the things, then you cannot create beneficial relationships.  From an agile perspective, the beneficial relationship that you create should only be beneficial based on your knowledge right now.  Tomorrow your knowledge changes, so the relationship may not be as beneficial as yesterday.  Time to change.

Building infrastructural architecture independently of functional requirements…

I am not convinced of the benefit of this approach.  In my limited experience, every business need defines the constraints or needs of the infrastructural architecture.  I find it hard to find the point of departure, yet there is a school of thought that suggests that function is orthogonal to the architecture.  Perhaps I just don’t understand this.  However from an agile perspective, I want to release early and there are many constraints on infrastructure from the business (for example, administrative processes like procurement of hardware).  I like to understand what these are early on, reach agreement on what we can release at the earliest and design accordingly.  Perhaps the first release is on lightweight infrastructure and that means we “limit” scalability.  So, I don’t design for beyond what I know is real.

Model Driven Architecture …

My view is more philosophical and abstract.  What is a model?  For me, a model is something intangible.  It is a way we understand something.  But we represent our models in many ways.  Through words in written or spoken conversation, in unstructured pictures, in structured notation like UML, even code is a representation of a model.

What do we mean by driven? I view it as a something that takes an input that produces an output.  In this case, we take an input, the model, and produce an output, an architecture.  So, I take an understanding of problem and use that to derive an architecture.  So, that’s nothing new here.  However, I don’t like to confuse driving out an architecture from a representation of the model.  That’s different.  Now we are going beyond thought processes  into mechanical processes.  Then the challenge is about how to apply the feedback to the representation of the model – and that is what will make you agile.  Too much for my small brain.

Plumbing …

Yup, we do too much hand crafted plumbing!  It’s something that we have been working on for a long, long time.  I think convention over configuration, dependency inversion, meta-programming are all attempts at addressing this problem.  Some early success that I have experienced is on taking a polyglot approach. I am not talking about mixing general purpose languages on one runtime only.  I am also including domain specific languages. I’ve had some early success where using DSL to describe functional intentions and then generating a large portion of the plumbing.  Where I’ve suffered is when I mix concepts from different domains.  There is the domain of plumbing and the domain of the business.  Whenever I’ve mixed the two, it pains later rather than sooner.  Right now, the only way I’ve had some success is with aspect orientation and meta-programming.

@StatelessSessionBean …

Chris Naidoo is right.  That thing called J2EE and subsequent versions is just horribly broken.  It’s broken encapsulation and a whole lot more.  The fact that we now must use an annotation and not implement an interface is immaterial.  Both result in the same pain – mixed concepts (see plumbing above).  Annotations should be specific to the business such as @RecalculateCostsOnRerouteOfCargo can be used as an interception point for injecting a rule on a class or method.

I would go even further and say that the POJO JavaBean specification is also broken.  Why on earth must I have a no-argument constructor and accessors and mutators.

Last thoughts …

I may have missed some of the other discussions but these are the ones that I woke up with this morning. In general, my observation is that we need to be very concrete very early if we want to be agile, even in architecture.

I will be running a 6 hour long session at the Scrum Gathering in Cape Town in September titled Modeling Out Loud.  I’m now convinced that the Scrum tribe are weird.  They call these sessions Deep Dives.  Presumably, you need to carry enough oxygen to survive the session.

I think I’m going out on limb here because I will be challenging the value of Product Owners writing stories.  I’m also suggesting that when Product Owners write stories riddled with behavior then developers are disconnected from domain experts and you regress into a waterfall mode of execution fronted by a Scrum Board.  So be prepared to experiment with me and turn up your self-reflection to maximum level because we will challenge many assumptions.

I know it’s absolutely insane to try to reduce Eric Evans’ amazing book into just a few pages, but stupidity won.  I think it’s still useful as a “next to the coffee mug on your desk thing” if you’re just starting off with DDD.  So download the free Domain Driven Design Reference Card at http://refcardz.dzone.com. Small warning: it’s not useful unless you’ve read Eric’s and/or Jimmy’s book or have attended a DDD course.

I’ve tried to keep it true to the book.  I’ve aslo added a reference to a couple of additional patterns right at the end, after some quick chats with Eric and Jimmy.  Given the space constraints, I decided to leave out the CQRS work.  It feels better anyway, since this meant as a cheat sheet for people starting out.

Last week on the factor10 DDD course in Cape Town, the question of reusability came up again.  It’s the same old object orientation promise of “Just do OO and you get phenomenal reuse for free”.  Today, I was refactoring some code with another developer at a client and I extracted some lines into a few private methods just to clean up a really fat loop.  The initial reaction from the other developer was “That’s an overkill because you won’t reuse that method”.  My spontaneous reaction was “Readability is the real reusability”.

It’s true, the method won’t be reused.  It’s also true that most us were taught in some Programming 101 course that you should create a method, function, procedure only if you are going to call it more than once, otherwise just leave it all inline.  I value ubuntu coding, and so I have learned to unlearn that naive rule.  When I make my code more readable, I get more reuse out of it.  The reuse I value is not really about the number of repeated method calls or number of inherited classes.  I value the increased reusability that is achieved when more developers are able to read my code and walk away understanding my intention, clearly and unambiguously.

Let me put it another way.  Your code is a representation of your model.  Your model should be used to drive all collaborative discussions about the solution.  That’s where you get the real reuse in your model.  If people can’t understand your model, then your model can’t be re-used for further discussions.