Are They Really Requirements?

The paradigm we get from the waterfall model is that a client states their requirements and they lead unidirectionally to the specification for the system. We already know from the popularity of the Agile methods that waterfall is not the correct model, that for many projects it is more productive to approach it as an artistic product and make many iterations that can be shared with the client. The benefits of this approach have been well documented but it still leaves the idea that there are some set of requirements that just need to be uncovered and refined. I now believe this is a fatal flaw in this part of even the Agile methods.

Iterative methods gain their power from the inclusion of the client in the design process. In the older waterfall approaches, after the requirements were documented and signed off, the client would often see little progress (except bills and excuses why the project was behind schedule) until an advanced level of testing allowed the client to see the complete system as it is intended to work. The pain this caused when it was realized that what was built was not an acceptable solution to the client's problem was always significant since so much had already been sunk into the wrong solution. Agile at least boxes the risk into a single iteration and if they are small enough, the damage can be limited. One good trait of all these Agile methods is that they support faster failure of dysfunctional projects.

Clients have always had misgivings about requirements signoffs. While they could not articulate it, they felt they were being setup for failure. Their business expertise did not prepare them for the task of directly specifying the product they needed nor is the average business analyst prepared to completely understand the business function that is within the scope of development. Neither is generally prepared for the design tradeoffs that are often done without any direct client involvement, even if the team is articulate enough to explain how a particular design decision impacts the various emergent properties of the system under construction. The current methodologies simply don't work during the requirements elicitation and analysis phases of even the most Agile methods. Instead they substitute what I like to call the waving of the hands form of requirements where everyone simply talks about what is needed, very often in "I'll recognize it when I see it" kind of terms. The design team does their best to interpret these statements, goes away and comes back with something that can be critiqued. The progressive elaboration of models and prototypes will allow an experienced team to eventually drive to a solution.

So what is wrong with this approach? After all, it does produce a solution. Is it optimal? Who knows? Is there any traceability to the design decisions made? Probably not. Does this sound like engineering? Emphatically no. We can do better.

What this approach lacks is the top-sight and planning that enable an architecture centric approach. Many solutions do not depend upon an architecture centric approach to achieve business success. When the solution is self-contained, highly derivative of a prior effort or does not have exceptional quality requirements, the emergent properties of the system will probably not be difficult to achieve when there is little or no "big analysis up front." But this is not the forefront of software engineering today and the solution to these challenges has not yet been found.

Emergent properties of a software system do not derive from one or even a small number of design decisions made when designing the product. Rather they emerge from a collection of many, most or sometimes all of the elements that comprise the system that have cross-cutting concerns addressed in a manner that allows the ensemble to achieve the collective goal. When the top-level decomposition of responsibilities has been properly done, these emergent properties can be achieved by independent developers working on sub-systems within the larger ensemble. But too often poor choices made in the first few design decisions can block the achievement of an emergent behavior even when all purely functional properties exist in the finished product. If the emergent properties that exist do not satisfy the business need, the product is rejected. But if the tradeoffs provide a product that "satifices", the product will be accepted and since the knowledge of what might have been is at best speculative (at worst, vindictive), the missed opportunity will never be known.

This can be improved by recognizing the key decision making role the client plays throughout the design process. The key challenge faced in trying to include the client, though, can be easily seen in a near universal scenario. The client has established a timeline and budget for the project. Then the requirements gathering begins. At some point, an astute engineer will observe that it is possible to get the needed functions and qualities a, b, and c at levels of x, y, and z and this combination is judged unacceptable. The engineer turns to the client and says, which are you willing to sacrafice. The client says "none. I want them all." What is really being said here is that the client is abrogating their responsiblity to be a decision maker in the project. If the engineer is correct that the qualities cannot all be achieved simultaneously (time and budget being two of those qualities), then the decision is foisted upon a team member to make a decision for the client. Just as the client felt cornered when asked to sign off on the requirements document, so too does the designer feel abandoned just when he needs the client the most. This is, after all, a business decision, a business decision that can have real business consequences. What is needed is for the client to engage in a form of negotiation to explore the possibilities, ensure that it really is impossible to achieve all goals simultaneously and then to take responsibility for the ultimate responsibility with the help of the business analyst, architect or whoever is in the lead design role.

So you can see that it is not as if requirements are completely elaborated at the time the project team ordinarily asks the business to sign off on them. This is an important first step and one that cannot be taken lightly. But neither can this be seen as the final word for business input. For an architecture centric approach, it must include sufficient elaboration of the qualities that can only be achieved with cross-cutting concerns that span a large portion of the code base to be developed. For any development it must at least be accurate even if it is not complete. But the impact of the aspirational goals cannot be known until the design progresses to a lower level of design and only then can the implications of that set of aspirational goals be known. As soon as possible thereafter the client must be brought back into the design process to negotiate the tradeoffs that should be made.

This process is much closer to advocacy than it is to specification. As leverage points appear there is someone to argue for the most advantageous tradeoffs that achieve their client's goals. For the client representative(s), it is to collaborate with the chief designer. For the project team, it is to do the most professional job possible in predicting the properties that will be present in the final product extended from this design.

from

Tim Bender to me

show details Sep 10 (2 days ago)

In discussing a large software project with an artist, I conjured the analogy that a software product is like a painting. Each engineer is an artist with their own style and they must paint a small portion of a large masterpiece, often without ever being able to see the whole thing. Recently, I watched a movie which made me recall this analogy and I pondered it further as a way of explaining in quite a simple way some of the rather complex interactions that occur in software engineering.

The idea centers around giving groups the common task of creating the simple image of a house with a lawn, a small family, the sun, a bird, and a flower. The image would need to be simple enough to be easily reproduced by an individual, but complex enough to offer varying entry points for concept learning opportunities.

Some of these concepts are weak and need some fleshing out.
1. Requirement solicitation:
Scenario: Give a team a sheet of paper and some coloring pencils. Express to them the importance of this drawing and that it must look exactly like what is being requested. Tell them to draw "a house with a lawn, a small family, the sun, and perhaps a bird and flower or something". Being purposefully vague and leaving them to either create only the initial description, or go ask follow-up questions.
Challenge: Requesting help and/or more information.

2. Specifying interfaces:
Scenario: Give a team the exact image they are to produce and a collection of transparencies attached to construction paper (making them non-transparent). Tell the team that each person must draw something on their transparency. Inform that the transparencies will be stacked to create the complete image.
Challenge: Specifying interfaces clearly to minimize integration failures.

3. Organizing for a task:

Scenario: Give a team the exact image they are to produce and a blank canvas with some pens. Tell them that each of them must contribute something and that they will be asked to state their contribution. From there, let them self-organize.

Challenge: Skill auditing. Some members will be excellent at sketching/drawing. Some may be terrible. Those that are not gifted in this area could take on a small portion of the image or provide administrative support. A variation might include purposefully leaving out supplies that a team member must requisition.

I was curious if you would have any thoughts on this.

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Me? Have opinions? Perish the thought!

This is an interesting metaphor but I probably don't see it the same way you do.

On my visit to Vienna I had a curated tour of the Kusthistoriches (Art History) Museum. In the pre-20th century tradition of large art studios, it was common for the studio to accept commissions in very must the way you describe and in a way that does have some interesting parallels to software engineering. Each studio is headed by a master who is the creative genius that gave the studio its fame and provides the marketing effort to keep it employed. But given the output of the studio, it was not possible for the master to personally paint all the canvases. Raphael ran such a studio and we spent time talking about how to tell a Raphael from his hand versus one that he may have never touched.

In the studio system the various artists had their individual talents. The less talented might be relegated to painting landscape backgrounds, another buildings, etc. Only the most talented would paint the main subject which was always a human being. The ability to achieve life-like form and tone was prized and only the very best could capture the "essence" of a human subject. For historical paintings that had many figures, the master might paint a few of the figures but would allow the studio to fill in the remainder. This form or organization seems to be very similar to how a software project develops. There is someone with experience who is responsible for the early launch and concept. But what is different is that unless it is an architecture driven development, there is no chief designer who will oversee the design from start to finish. With each phase transition it is the project manager who oversees the progress toward the goal and not an architect. A project manager is usually more focused on the more mundane aspects of the project such as time and budget rather than the less externally visible properties of the system under development.

There is a fundamental difference between art and software. For art, the effect of the completed product is what is valued and not the qualities of the individual pieces, no matter how good. So it is with a software system. A property like security is not solely dependent upon any single component, although that cross-cutting concern will be seen in many of the modules. The lack of attention to even one point in the design can doom the security of the entire system. To one extent or another, this can be true of all the quality (non-functional) requirements placed upon the system. Performance is famously lost through a weak-link in the processing as is availability; modifiability by the inappropriate decomposition of the modules; usability by the lack of a facility for an un-do in the transactions. These qualities can be reduced to an engineering model that provides quantitative, or at least, testable properties. This is not true of art which is often said to lie in the eye of the beholder; not a good quality in an engineering project.

Ironically, I have seen many project proceed as if they were art project. The project management, the client, the business analysts, and the coders all proceed with the functional requirements only and wing it with the crap that is often offered as "non-functional requirements." This forces the team to make decisions for the client as to what qualities and what relative priorities to give to those qualities. This causes the client to not perceive the lack of some quality until they see an early prototype of the product, or worse, the finished product. Then, and only then, does the performance/availability/fault tolerance/usability/security get the attention that it deserved often with disastrous consequences to the design concepts that had guided the many hands that crafted the code.

The number 2 scenario sounds exactly like the way cell animation is done. I think the key difference here is that the transparencies are opaque and therefore block what is behind. This makes the "interface" irrelevant since there is no need for coordination between Bambi and the forest trees behind her. As long as there is no interleaving between two transparencies, there is no need for the careful coordination that is suggested with interfaces. Software, of course, is very different since most any decomposition of a function into smaller modules will create some form of interface that must be spec'd.

For any product that will be created by many hands I cannot believe that self-organization, as it is often understood, can work. I think most people take self-organization to be some form of egalitarian 'let's all get along' I do not believe this is what the Agile manifesto suggests. Rather I believe the Agile manifesto suggests that experienced and skilled professionals are more effective of organizing themselves for the task without an explicit plan from some "manager" who is not as experienced with the technology. However all the same roles will be filled. Group dynamics ensures that a leader will be selected and that the group will go through the steps of forming, storming, norming and performing. Self-organization will also do nothing to prevent the group dysfunctions that affect traditional forms of management as well.

Going back to your example, if a group of artists are given a commission and left to self-organize, the leader that emerges is not guaranteed to be the best artist. It is often true in engineering circles as well. Arrogance, self-confidence, domineering personalities are the most likely to be the group leaders. When this is also the most talented individual and has the leadership skills to bring the team along, the results can be striking. But it can just as easily lead to disaster or a mediocre product too.