Author: George Dinwiddie

George Dinwiddie is a Software Development Consultant and Coach with over twenty years of experience creating software ranging from small embedded systems to corporate enterprise systems. With a strong interest in lifelong learning, he has pursued more effective ways of creating software at the technical, interpersonal and organizational levels. As principal of iDIA Computing, LLC, he helps teams learn more effective software development techniques while accomplishing their current projects.

Accomplishing Organizational Transformation

Scaling Agile across the Enterprise attracts a lot of attention these days. There are a number of models suggesting ways to organize Agile development inside a sizable organization with a lot of teams. I suspect that all of these models share the same basic flaw—that you can do something the same way across a large enterprise. Even if your policy manual says exactly how to do something, people are people and there will be variations in understanding and execution. And how does a team self-organize in a prescribed manner?

Beyond that, there’s the problem of getting from current state to a future state that resembles the model. It does not work to “install” a new way of working across a large system composed of people and their interactions. Some people suggest starting the transformation with management, as that’s the “highest leverage point” and the “system’s major influencers.” Others suggest starting with the teams, because without competence at building reliable software (or other systems) in short cycles of small steps, you’re not going to get the benefits of Agile Software Development. I don’t think that either of these starting points work.

“When we try to pick out anything by itself, we find it hitched to everything else in the Universe” — John Muir Read More

What is the Right Length for a Project?

I’ve seen many comments on the topic of estimation in the past year, and I’m starting to notice some trends and assumptions in them. One of the common assumptions is that, given a particular team and amount of resources, there is a correct length to a project. A twin to this one is that there is a correct estimate that contains the same end date as the subsequent actual project performance. Read More

Why I Practice TDD

I was reading Laurent Bossavit’s book, “The Leprechauns of Software Engineering—How folklore turns into fact and what to do about it,” and came across his mention of “Comparing the Defect Reduction Benefits of Code Inspection and Test-Driven Development” by Jerod W. Wilkerson, Jay F. Nunamaker, & Rick Mercer. This struck me as an odd thing to study. Not only is Test-Driven Development not primarily about defect reduction, but the populations of defects it might reduce are likely to be very different from population of defects reduced by code inspection.

I then took a look at my own list of TDD studies and noted that most of these studies were focused on external quality as measured by absence of known defects, and time it took to develop the functionality. Keith Braithwaite, at Agile 2007, reported on internal quality, specifically Cyclomatic Complexity.

Quality and productivity are, of course, important things. And they’re easy to sell to some managers. Who could be against them? And I certainly wouldn’t continue to practice Test-Driven Development if it added defects or took a significantly longer time to create functionality. But that’s not why I practice TDD. Read More

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Managing Risk With Estimates

Used with care, software development estimates can help you manage project risks. They let you peer into the future, though only as well as your current understanding allows. Estimating based on what you know is easy. Estimating based on what you know you don’t know is possible. Allowing for what you don’t know you don’t know is prudent.

Managing risk is a dynamic process. I’ve seen people document a risk in a “Risk Register” document and promptly ignore it. That’s not management. Instead, consider different ways a risk might be reduced in likelihood or consequence. When time or cost is of the essence, think about how you’ll determine what you can afford, and when you need to take a second-choice approach. Read More

Dysfunctional Commitment

Team commitment is a wonderful and sometimes fragile thing. Many responses to my description of it are indications of how frequently the word “commitment” is used in a dysfunctional manner. Indeed, the post was prompted by similar conversations.

Believe me, I’ve seen these dysfunctions many times. They are so numerous and varied that no catalog of them could be complete. It’s not the word, commitment, that causes the problems, however. And avoiding that word will not solve the problems. Instead, we have to look at the behavior and attitudes behind the problems in order to reliably recognize them and choose strategies for correcting them. Read More

Team Commitment

Most Scrum teams estimate their top priority stories, select those stories that add up to their historical velocity for their sprint backlog. Some teams simplify this by merely counting the stories, or using the mathematical reciprocal, cycle time. Others make it more complicated, calculating the effect of days off and other known distractions from the work.

However they calculate it, some people put a lot of faith in the historical data to guide the future. “It’s data,” they say, “it’s better than guesses and not subject to cognitive bias.” Not all data is easily measured and converted to numbers, though. Limiting yourself to this initial calculation is, itself, an example of anchoring bias. Read More

Estimation as Hypothesis

Experimentation is a powerful learning tool. When I was young, I performed scientific experiments by mixing chemicals together to see what they would do. I learned that most random concoctions from my chemistry set would make a brown liquid that was often hard to clean out of a test tube. I learned that sometimes they would create very smelly brown liquids. These were not really experiments, however, and I didn’t really learn from them. Instead, these were activities and I collected anecdotes and experiences from them.

The scientific method rests on the performance of experiments to confirm or deny a proposed hypothesis. Unless you can propose a hypothesis in advance, you cannot design an experiment to test it. Until you test the hypothesis, you haven’t really learned anything. Read More

How do we estimate?

There have been some web posts and twitter comments lately that suggest some people have a very narrow view of what techniques constitute an estimate. I take a larger view, that any projection of human work into the future is necessarily an approximation, and therefore an estimate.

I often tell people that the abbreviation of “estimate” is “guess.” I do this to remind people that they’re just estimates, not data. When observations and estimates disagree, you’d be prudent to trust the observations. When you don’t yet have any confirming or disproving observations, you should think about how much trust you put into the estimate. And think about how much risk you have if the estimate does not predict reality.

This does not mean, however, that you have to estimate by guessing. There are lots of ways to make an estimate more trustworthy. Read More