Skip to main content

A requirements notation

Recently I have been doing requirements in a few separate places. I got the notion into my head that there was no good notation for describing requirements, particularly non-functional requirements. UML has a diagram for use cases, but no diagram for requirements per se.

So this is the legend of the notation I drew up:

Legend

In the Critical Factors Analysis method, your identify three classes of requirements: the goals that you want to achieve, the critical factors and conditions that must be satisfied to achieve the goals and the measurable requirements on the solution that will meet the goal. This methodology is powerful primarily because it can act as a forcing function to ensure completeness of requirements.

I have had difficulty in getting people to understand the difference between goals, CFAs and requirements. I have also had difficulty getting people to distinguish requirements from solutions! (Everyone has their favorite piece of technology that absolutely must be part of the final product.

My take is that requirements are problems to be solved, not solutions. Preferably, these problems are problems that customers have; not problems developers have!

Diagrams like this

Ra Cfa
can act as very effective indexes into a textual description of the factors that go into a successful project.
Labels:

Popular posts from this blog

Existential Types are the flip side of generics

Generic types, as can now be seen in all the major programming languages have a flip side that has yet to be widely appreciated: existential types. Variables whose types are generic may not be modified within a generic function (or class): they can be kept in variables, they can be passed to other functions (provided they too have been supplied to the generic function), but other than that they are opaque. Again, when a generic function (or class) is used, then the actual type binding for the generic must be provided – although that type may also be generic, in which case the enclosing entity must also be generic. Existential types are often motivated by modules. A module can be seen to be equivalent to a record with its included functions: except that modules also typically encapsulate types too. Abstract data types are a closely related topic that also naturally connect to existential types (there is an old but still very relevant and readable article on the topic Abstract types have...
Read more

Minimum Viable Product

When was the last time you complained about the food in a restaurant? I thought so. Most people will complain if they are offended by the quality or service; but if the food and/or service is just underwhelming then they won't complain, they will simply not return to the restaurant. The same applies to software products, or to products of any kind. You will only get negative feedback from customers if they care enough to make the effort. In the meantime you are both losing out on opportunities and failing your core professional obligation. Minimum Viable Product speaks to a desire to make your customers design your product for you. But, to me, it represents a combination of an implicit insult and negligence. The insult is implicit in the term minimum. The image is one of laziness and contempt: just throw some mud on the wall and see if it sticks. Who cares about whether it meets a real need, or whether the customer is actually served. The negligence is more subtle but, in the end, ...
Read more

Hook, Line and Sinker

It is well documented that people’s #1 fear is speaking in public ! Effective and efficient public speaking is a whole topic in its own right; but a few simple tips might help to both improve your effectiveness and help to reduce the anxiety. You may be called on to talk about your work at very short notice; or you may have a week’s notice; and you may be required to give a formal slide show or just a brief verbal update. Many, if not most of the issues, are the same. The Hook Newspaper editors call the first paragraph of an article ‘the hook’. Its meant to hook you into reading the rest of the piece. On the other hand, the classical ‘say what you are going to say, say it, and say what you said’ approach gives people plenty of time to switch off. The hook may be playful, it may be controversial, but it must communicate why the listener should pay attention. The Line Its a conversation! Even if no one says anything they are listening and thinking; and maybe replying to you in their head...
Read more