Paired Work

The concept of pair programming was popularized by eXtreme Programming. And it's true that pair programming can result in faster elapsed development time and higher quality. But pairing as a technique can be useful for improving the time and quality of a wide variety of activities. I'll reference the use of pairing many times throughout this book.

Picture in your mind you and your pair driving in an off-road rally race. The terrain is rough and rugged. The driver needs to pay attention to the road and constantly adapt. The navigator needs to pay attention to the map, keep the driver headed the right direction and aware of obstacles. It's noisy, bumpy and chaotic in the car. While the work the pair engages in may vary wildly, there's a general structure and flow to pairing that will always apply. Keep the off-road rally metaphor in mind as we discuss that structure.

Pairing Session

When coming together to pair it's important to set a timebox, rigid or approximate, for the session. Working together as a pair, when done well, increases the rate of any activity. Information flows very quickly. This makes pairing exhausting. Understand that pairing can happen in several sessions and set a timebox for each specific session.

For our rally racers they may agree to drive till lunch, then stop for a break. Set Goals

With your partner discuss goals for a particular pairing session. It helps me to finish this statement -

"This pairing session will be successful if…"

For our rally racers they may agree that they'd be successful if they get to the washed out river bed ten miles from here.

Driver performs the work

In most pairing activities one person takes the lead. In programming this means controlling the keyboard to write code. In other types of activities it may mean leading a discussion, drawing on the whiteboard, or using index cards to construct a model.

While keeping the goal in mind, the driver focuses on short term activities they can perform to move forward.

For our rally racers the driver keeps his eyes on the road and his hands upon the wheel. He watches for bumps, holes in the road, and other obstacles.

Navigator keeps focus long range

While the driver focuses on immediate actions, the navigator pays attention to longer range goals for the session. He pays attention to what the driver is doing, pointing out possible mistakes. But mostly he focuses on the results of the pairing exercise and how they could be improved.

For our rally racers the navigator alternates between looking at the road immediately ahead, looking at the map to see what's over the next hill, and pointing out obstacles the driver may not be aware of. The navigator helps plot a course to get the car to the agreed on destination.

The driver should try to think out loud

People who've paired together frequently begin to read each other's body language and recognize each others body patterns. They seem to be able to communicate without needing words to do so. But, for most of us who haven't reached that level of communication nirvana, we need some other approach to let our partner know what we're thinking.

Think Out Loud is a technique often used in usability testing, but it works well in pairing. As the partners are working, they should attempt to repeat their thoughts out loud to their pair. Usually the driver spend the most time thinking out loud telling the navigator what he's thinking and what his intentions are as he does work. The navigator listens closely and mentally checks that the words the driver says match the action he's actually taking. The navigator makes sure the actions taken by the driver are helping the pair reach their goal.

At times the navigator will think out loud as he's considering the pair's current progress towards their goal. This may result in a discussion that could turn into planning for re-planning.

Picture our rally race driver shouting out what he's doing as he drives. 'I'm heading for that hill over there, but I'm going to veer around those holes in the road!"

Plan and re-plan frequently

Planning happens frequently during pairing. The driver may make some choices about a series of next steps to pursue. The navigator may make some observations that cause the pair to question whether their goals are really being met. In both cases the pair may stop for a minute and plan or adjust an existing plan - re-plan.

It's common in a pairing session to record short term plans on an index card, set of post-it notes, or a list on a whiteboard.

For our rally racers they may have encountered a ravine blocking their current path. They may stop the car and together look at the map to choose a best path around before continuing on their way.

Pass Control

In pairing especially, the driver and navigator roles aren't set. Frequently the pair changes places. In programming this happens when the programmer shifts the keyboard to his pair, or the pair pulls it from the navigator. At a whiteboard, this may happen by grabbing a marker and starting to draw. Expect passing control to occur. Consider developing an easy way to communicate that you'd like to give up or receive control.

At times it's both possible and tempting to have both drive. But, then no one's keeping an eye on the road and you may end up in a ditch.

Our rally driver may be exhausted from hitting several big bumps and negotiating some tight slippery turns. He may find he's not thinking as clearly. He may ask the navigator to drive for a while so he can change to focus on the long range picture and give his short term thinking mind a rest.

Avoid driving from the back-seat

At times the navigator will start spending more time focusing on the immediate actions of the driver instead of the pairing session goals. You may notice the navigator comments more and more about specific actions made by the driver and less about the quality of the result. I call this back-seat driving, and it's not a good thing.

When the navigator begins to assume driving responsibility, it may be time to pass control. If the pairing session has been going for a while, it may be a sign that the session has lasted too long and it's time for a break. All work isn't suitable for pairing. If the job of navigation isn't suitably challenging enough, this can result in the navigator not having much to focus on and to begin back-seat driving. Possibly the activity you're engaged in shouldn't be paired on.

Consolidate and reflect at the end of a pairing session

At the end of the pairing session it's time to stop and look back at what work was completed. Both parties should collect observations about the work done. Was the goal reached? What was learned about the problem along the way? Is there anything we can write down to summarize this work? Use consolidation to capture what happened and measure progress towards your goal.

Reflect also on how pairing together is working. Does one or both parties need to think out loud? Should planning and re-planning occur more or less frequently? Should control be passed more often? "Maybe you should stop back-seat driving so much."

Use reflection to look at your pairing process and make changes to help things go better during the next pairing session.

Our rally racers stop for a mid-day break. They both look at the map and mark the distance they've covered so far. They quickly estimate how much longer they're likely to take. They discuss the problems they encountered on this road and some possible strategies to avoid them. They also discuss a strategy of switching driver and navigator responsibilities more often so they stay fresh.