Tag Archives: Pair Programming

All Team Quality Standards Should Be Part of the Definition of “Done”

The other day a technology leader was asking questions as if he didn’t agree that things like pair programming and code review should be part of the Definition of “Done” because they are activities that don’t show up in a tangible way in the end product. But if these things are part of your quality standards, they should be included in the definition of “Done” because they inform the “right way” of getting things done. In other words, the Definition of “Done” is not merely a description of the “Done” state but also the way(s) of getting to “Done” – the “how” in terms of quality standards. In fact, if you look at most of any team’s definition of “Done”, a lot of it is QA activity, carried out either as a practice or as an operation that is automated. Every agile engineering practice is essentially a quality standard and as they become part of a team’s practice, should be included as part of the definition of “Done”. The leader’s question was “if we’re done and we didn’t do pair programming and pair programming is part of our definition of “Done”, then does that mean we’re not done?” Which is sort of a backwards question because if you are saying you’re done and you haven’t done pair programming, then by definition pair programming isn’t part of your definition of done. But there are teams out there who would never imagine themselves to be done without pair programming because pair programming is a standard that they see as being essential to delivering quality product.

Everything that a Scrum Development Team does to ensure quality should be part of their definition of “Done”. The definition of “Done” isn’t just a description of the final “Done” state of an increment of product. In fact, If that were true, then we should be asking why anything is part of the definition of “Done”. This is the whole problem that this artifact solves. If this were the case, the team could just say that they are done whenever they say they are done and never actually identify better ways of getting to done and establishing better standards. We could just say (and we did and still do), “there’s the software, it’s done,” the software itself being its own definition of “Done”.

On the contrary the definition of “Done” is what it means for something to be done properly. In other words, it is the artifact that captures the “better ways of developing software” that the team has uncovered and established as practice because their practices reflect their belief that “Continuous attention to technical excellence and good design enhances agility” (Manifesto for Agile Software Development). The definition of “Done” is essentially about integrity—what is done every Sprint in order to be Agile and get things done better. When we say that testing is part of our definition of “Done”, that is our way of saying that as a team we have a shared understanding that it is better to test something before we say that it is done than to say that it’s done without testing it because without testing it we are not confident that it is done to our standards of quality. Otherwise, we would be content in just writing a bunch of code, seeing that it “works” on a workstation or in the development environment and pushing it into production as a “Done” feature with a high chance that there are a bunch of bugs or that it may even break the build.

This is similar to saying a building is “Done” without an inspection (activity/practice) that it meets certain safety standards or for a surgeon to say that he or she has done a good enough job of performing a surgical operation without monitoring the vital signs of the patient (partly automated, partly a human activity). Of course, this is false. The same logic holds true when we add other activities (automated or otherwise) that reflect more stringent quality standards around our products. The definition of “Done”,therefore, is partly made up of a set of activities that make up the standard quality practices of a team.

Professions have standards. For example, it is a standard practice for a surgeon to wash his or her hands between performing surgical operations. At one time it wasn’t. Much like TDD or pair programming, it was discovered as a better way to get a job done. In this day and age, we would not say that a surgeon had done a good job if he or she failed to carry out this standard practice. It would be considered preposterous for someone to say that they don’t care whether or not surgeons wash their hands between operations as long as the results are good. If a dying patient said to a surgeon, “don’t waste time washing your hands just cut me open and get right to it,” of course this would be dismissed as an untenable request. Regardless of whether or not the results of the surgery were satisfactory to the patient, we would consider it preposterous that a surgeon would not wash his or her hands because we know that this is statistically extremely risky, even criminal behaviour. We just know better. Hand washing was discovered, recognized as a better way of working, formalized as a standard and is now understood by even the least knowledgable members of society as an obvious part of the definition of “Done” of surgery. Similarly, there are some teams that would not push anything to production without TDD and automated tests. This is a quality standard and is therefore part of their definition of “Done”, because they understand that manual testing alone is extremely risky. And then there are some teams with standards that would make it unthinkable for them to push a feature that has not been developed with pair programming. For these teams, pair programming is a quality standard practice and therefore part of their definition of “Done”.

“As Scrum Teams mature,” reads the Scrum Guide, “it is expected that their definitions of “Done” will expand to include more stringent criteria for higher quality.” What else is pair programming, or any other agile engineering practice, if it is not a part of a team’s criteria for higher quality? Is pair programming not a more stringent criteria than, say, traditional code review? Therefore, any standard, be it a practice or an automated operation, that exists as part of the criteria for higher quality should be included as part of the definition of “Done”. If it’s not part of what it means for an increment of product to be “Done”—that is “done right”—then why are you doing it?


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Link: Short Article About Pair Programming

Pair Programming Economics by Olaf Lewitz describes three activities in programming: typing, problem-solving and reading code. How does pair programming help? By making the balance between those three activities better.


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Agile Estimation and Pairing

I just read a recent article on PMHut called “Schedule Questions: Pair Programming and the PNR Curve“. There is much in this article that is important for agile project management… and much that should be avoided at all costs!

Estimating Projects

The bulk of the article is an explanation of the PNR curve (Putnam Norden Rayleigh curve). The explanation is sufficient and can be checked against other web articles about software estimation. The basic idea of the PNR curve is to find an ideal number of people with which to staff a project based on an estimate of overall project size (e.g. 72 man-months).

Take a moment to go read Fantasy Estimation (the comments here provide good additional material).

It should be clear now that any initial sizing estimate based on units such as man-months is ridiculous. So what is our alternative? What about an agile approach to estimation and planning?

Agile Estimation

Well, at a minimum, in an agile approach to estimation, we need to resolve some of the problems identified in “Fantasy Estimation”. So, we:

  1. Get the whole team that will be doing the work to do the estimation
  2. We weight estimates based on team maturity, knowledge of tools, knowledge of the business domain and the physical proximity of team members to each other
  3. We adjust our estimates of work remaining based on our results for work completed

The great thing about an agile approach is that it allows all these things to be done and to be done well. Scrum has a specific set of “Drag Factors” that can be used to weight the team’s estimates. And using a team’s past estimates vs. “actuals” is possible on an iteration by iteration basis… and this is possible because every iteration the team is doing the “same thing”: delivering an increment of valuable results (working software, edited video, organizational change, whatever is contributing to the project goals).

The other thing that agile methods allow is to make a distinction between estimation for planning and estimation for commitment.

So. It’s cool to learn about the PNR Staffing curve and the thinking behind it. It’s a little scary to see it being applied in an agile context when we have tools that are much better.

Pairing and Estimation

At the end of the PMHut article, the author, Mike asks a question:

What about pair programming? When using pairs on a team we could either:

  1. Continue as is, use the model to determine optimal team size and then encourage pairing to increase efficiency.
  2. Treat a pair as one hyper-effective person, so count pairs not individuals and increase team sizes accordingly.

This second option seems counter intuitive to agile, we strive for small teams to reduce communication channels, so I’m not convinced by this idea. I would be very interested to hear people’s thoughts on agile staffing curves. So, lots more questions than answers in this post, please let me know if you have any research or thoughts on the matter.

I wrote in response:

Mike, I feel like the options you present in your question at the end actually miss the true point of pairing which has to do with communication. I have never seen pairing done in such a way that two people always work together as a pair. Rather, pairing is promiscuous: people switch pairs frequently throughout a day, iteration or project. This switching has two communication effects: 1) the human interaction and gradual diffusion of information as people switch pairs 2) helping everyone understand all parts of the work as a result of frequently working on many different things. From an estimation standpoint, I expect that neither of your two options is quite right. Rather, the third option is to continue as is with existing estimation and then encourage pairing to increase communication. Increased communication shows up in a number of different ways, not just efficiency: risk mitigation, accelerated individual and team learning etc.

I would like to expand on this just a little. To me, pair programming or pair work of any kind has always been able to provide a number of benefits to projects. Problem avoidance is one benefit (lower defect rates, better code quality through constant inspection, spotting each other). Better communication is another benefit. Increasing the Truck Factor is yet another benefit.

None of these benefits have any direct bearing on estimating a project at the start, particularly since most projects sacrifice quality for schedule. From an agile perspective, since planning estimation is not commitment, it actually doesn’t even really matter! Get a conservative estimate for you project using whatever method you like, then start working and get a commitment velocity and see what the team can really do.


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Pair Programming in Software Development

Pair programming appears to be the most controversial of all the Extreme Programming (XP) practices. It invokes such a violent emotional response in some people that they quickly dismiss all of XP just because of this one practice.

Continue reading Pair Programming in Software Development


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