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The next practice I want to discuss is a very important one

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in XP, and also one of the scandal, controversial, and it's

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the practice of pair programming. What does it mean? It means

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that all production code is written with two people looking at one

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machine. And not that they're, they're working with one keyboard and

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one mouse or they're not just interfering and writing on each other's

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code. And the way in which that happens is by playing

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different roles at different times. So the two developers alternate between the

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role of programming and strategizing, where strategizing means, for example,

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looking at the code that has been written and thinking whether

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that would work. Or what other tests that are not there

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might not work, given the way the code is being written.

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Or maybe looking at the code from a, you know, slightly

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detached perspective and trying to figure out whether the code can

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be made simpler, more maintainable, more efficient. And interestingly, there are

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measurements, there are studies that

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suggest that development productivity with pair

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programming is similar to that of two people

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working independently. And that answers one of the

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main objections against pair programming, which is why

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should I put two developers together, which is

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going to cut their productivity in half. It is

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not. Studies shows that that does not happen.

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And that the resulting code can actually benefit

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from the fact that two developers are working together.