7 Reasons Why Pair Programming Makes Sense

Did I mention that I like pair programming? Here are some reasons why it’s good for you and your boss.

More Trucks

The higher the truck number of your team, the more resilient it is to losing people. Pair programming spreads knowledge of the code around the whole team meaning each team member has a much more broad knowledge of the system than on a traditional team.

Free Training

Every time I pair with someone, I learn at least one new trick, be it a keyboard shortcut for my editor, a new command-prompt command, or a language idiom. This training costs nothing and builds the confidence of even the most junior team members who always have something to contribute, to say nothing of how much they will learn from sessions with their more senior colleagues.

Team Bonding

Working together in pairs breaks down barriers between people much more quickly than when they are working alone, and provides a natural environment for teams to learn to trust one another, and enjoy one another’s company. These are vital attributes that will get your team though the tough times, ensuring they can pull together when necessary.

Better Designs

Experienced programmers know that coding is much more a process of design than of mere implementation. When subjective design decisions are taken by at least two people on the team, those decisions have much more authority and are more likely to be understood and accepted by the rest of the team than if they had been taken alone. When one member of the pair has a good idea for a solution to a problem, this may stimulate an even better one from their pair. Science says so.

Less Bugs

The perpetual code review that’s done during a pairing session not only produces better designs, but it also catches a lot more defects as they are written. Pairs will tend to write more thorough automated tests, and are more likely to spot holes in logic that would otherwise have to be picked up by subsequent manual testing.

More Fun

Generally, programming in pairs makes for more a more relaxed and enjoyable atmosphere in a team. People become comfortable with their own strengths and weaknesses and are able to talk and joke about their work much more readily, since they are already used to that dialogue. This is obviously terrific for morale and staff retention.

More Focus

Pair programmers do not check their emails when they’re waiting for a script to run, disappear into their inbox for 20 minutes, then come back and have to remind themselves what on earth they were doing. When they hit a little break-point, they review what they’ve done so far and make a plan for their next steps. They stay focussed. Twitter can wait.

Agile / Lean Software Development

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Personas for Debugging Pair Programming Session

As I may have mentioned I’m running a session at Agile 2009 called ‘Debugging Pair Programming’. There’s a preview of the session tomorrow night at Skills Matter and I’ve just finished preparing for it.

Mind if I run a couple of things past you?

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Debug Pair Programming with Me in London

I’ll be running a preview of my Agile 2009 workshop ‘Debugging Pair Programming’ at Skills Matter on Monday 10th August.

If you’re on a team that’s using or trying to adopt pair programming, this is a great chance to explore and understand some of the complex reasons why this is such a difficult skill to master.

The session is free, so sign up soon to avoid disappointment: http://skillsmatter.com/event/agile-scrum/debugging-pair-programming

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If Code is Written Solo in a Forest, Does it Make a Sound?

I’ve written before about my views on the importance of pair programming as a way of building a common conciousness in a team. When two people work on a piece of code together, not only is it instantly reviewed for correctness and readability, but already two people on the team understand exactly why the code is like that – the design decisions and trade-offs that went into building it that particular way, and are aware of any re-usable modules, patterns, idioms or conventions that emerged during the coding session. When each of those people goes off to work with other members of the team, those memes propogate around the room surprisingly quickly.

When you write code alone, you immediately lose this benefit, and on a system of any significant size, this is really important. You might be writing terrific code, making great decisions and innovating really creatively, but if nobody on your team has experienced those decisions and innovations with you as they happened, all you are really sharing with them is the much more shallow end result: the code.

It’s almost like they never even happened.

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XP Day 2008: Debugging Pair Programming

At XP Day 2008 I proposed an open-space session on pair programming. Specifically, I wanted to explore the reasons why programmers might not want to pair, or find it such an unpleasant experience that they’re put off doing it again.

Judging by the great number of people who turned up and stayed for the session, it’s clear I’m not the only one who is struggling with these issues, adding more weight to my suspicion that pair programming is the hardest of all the XP practices to master.

I worked with Laura Plonka to devise and run the session. Laura is researching her PhD thesis on pair programming, using video footage to analyse pair programming sessions, then running a retrospective where the pair get to debrief and share their experiences of the session.

Despite the huge contribution from everyone present, at the end of the hour, I felt as though we had only started to scratch the surface of the problems we’d identified. It seems as though too many teams, even at organisations who are ostensibly keen to embrace ‘agile values’, suffer from some toxic cocktail on this menu of dysfunction:

  • an agile-zealous leadership which forces people into unwilling or poorly-chosen pairs
  • a culture that, at some level, values heroics over craftsmanship, such that programmers may feel a subtle or unconscious reluctance to chose to pair on a task unless it looks utterly daunting, and there could be no shame in being seen to ‘ask for help’.
  • a team that disagrees on the types of tasks that should be done as a pair
  • team members who are far enough along the autistic spectrum (as Joseph Pelrine and Ben Fuchs pointed out, we have a higher proportion of these than many other professions) that they find the level of inter-personal communication required for pairing difficult or impossible.
  • ‘Experts’ on the team who feel that pairing with less experienced members of the team will slow them down too much
  • ‘Newbies’ on the team who are afraid to ask for help, or feel the work they’re doing is too mundane to need to be done in a pair

There were masses more issues brought up – these are just the main few that I can remember now. Hopefully more people will write up their sections on the session’s page on the XP Day wiki, or maybe comment on this blog post.

I spent the latter half of the session in a small group discussion the influence management can have on the adoption and enjoyment of pair programming. Paul Field and I enumerated the benefits that teams who embrace pair programming and create a culture where it works, can enjoy:

  • Better system knowledge across the team (higher truck number)
  • Skills transfer between team members (free training)
  • Team bonding
  • More defects found & found earlier
  • Better solutions/designs
  • More fun (better staff retention & morale)
  • Better focus (less time wasted in email / facebook)

It’s worth holding onto this list, and thinking about it when experimenting with pair programming within your team. Not all these benefits will be immediately apparent, so it’s worth being patient and trying to figure out ways to measure them to give you feedback as to the success of your experiment.

Another great idea I heard for teams that want to try pairing but are unsure as to which tasks are appropriate: try doing every task in a pair for at least five minutes. If, after that time you both agree that it’s a waste of time to do it as a pair, you can split up.

I still feel like there’s huge amount of work to be done to collect and disseminate the patterns and anti-patterns around pair programming, but I’m glad to have at least stirred up the pot a little. Thanks to everyone who turned up and contributed so much, and thanks especially to Joseph and Ben for organising a follow-up session later in the day where we had the opportunity to drill down into those psychological barriers a little bit more. Great stuff.

Agile / Lean Software Development

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“Total Programming” and the XP Team

Pair programming brings a great many benefits to a team that’s truly mastered it.

Those of us who are lucky enough to have experienced working on a really effective XP team know about that almost magical thing that starts to happen when the barriers between different members of the team break down, egos and code ownership are cast aside, and the team starts to evolve the codebase as one, mighty, coding machine. It’s truly a joy to be a part of, or even just to watch.


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