When, if ever, is “number of lines of code” a useful metric?

Question

Some people claim that code\'s worst enemy is its size, and I tend to agree. Yet every day you keep hearing things like

• I write blah lines of code in a day.

Answer 1

I'd say it's when you're removing code to make the project run better.

Saying you removed "X number of lines" is impressive. And far more helpful than you added lines of code.

Answer 2

When determining level of effort (LOE). If you are putting together a proposal and you will have the roughly the SAME engineers working on the new project, then you might be able to determine how many engineers are needed for how long.

Answer 3

I'm surprised nobody has mentioned Dijkstra's famous quote yet, so here goes:

My point today is that, if we wish to count lines of code, we should not regard them as "lines produced" but as "lines spent": the current conventional wisdom is so foolish as to book that count on the wrong side of the ledger.

The quote is from an article called "On the cruelty of really teaching computing science".

Answer 4

When bragging to friends.

Answer 5

It is useful in many ways.

I don't remember the exact # but Microsoft had a web cast that talked about for every X lines of code on average there are y number of bugs. You can take that statement and use it to give a baseline for several things.

• How well a code reviewer is doing their job.
• judging skill level of 2 employees by comparing their bug ratio's over several projects.

Another thing we look at is, why is it so many lines? Often times when a new programmer is put in a jam they will just copy and paste chunks of code instead of creating functions and encapsulating.

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I think that the I wrote x lines of code in a day is a terrible measure. It take no account for difficulty of problem, language your writing in, and so on.

Answer 6

It is a very usefull idea when it is associated with the number of defects. "Defects" gives you a measure of code quality. The least "defects" the better the software; It is nearly impossible to remove all defects. In many occasions, a single defect could be harmfull and fatal.

However, it does not seem that nondefective software exists.