In this topic I will describe some interesting metrics that I use to help me determine the experience of a developer. These metrics are totally subjective (ZOO(1)) and can mean different things to different people. Here you can find what they mean to me. Make your own decisions for yourself and remember that I am only human thus fallible.

Moreover I do not claim that this is a complete list of metrics for judging the experience of a developer. This would violate ZOO(2).

WLOC = Written Lines of Code

This is not actually my idea, but I can’t remember whose it was. Probably Joel’s.
WLOC is the estimated total number of lines of code the developer has written in her programming career so far. Most likely a developer that has WLOC=300K is more experienced than a developer that has WLOC=50K.

ILOC = Installed Lines of Code

This is the total number of lines of code that the developer wrote that are installed on user machines. If I have contributed 10.000 in a program and that program is installed on 100 machines, then I score ILOC=1M from that program.
The more the machines the higher the number gets and it can get pretty high, so we are practically interested in the magnitude of the number, not the actual number.
That’s why it doesn’t make a real difference what language you use for this metric. You write more lines in C than in Lisp, but it’s the magnitude of the number that matters.
A developer scoring an ILOC of 1G is probably much more experienced from a developer scoring 1M.

DELOC = Daily Executed Lines of Code

This is the total lines of code that the developer wrote that get executed daily on all user machines. This is pretty hard to measure so an estimate is enough.
Let’s suppose that we have a 200K LOC system. You might have written 10K lines, but these lines get executed 5 times a day on 100 machines, while somebody else wrote 2000 lines of code that execute several thousand times a day on 5000 user machines (and I am not talking about message loops here).
Usually these 2000 lines are more critical (that’s why they get executed so often) and much harder to get right since they get exposed to more testing from the user.

DMTS = Daily Monetary Transactions Sum

This is the sum of money involved in transactions your code processes every day. Obviously it takes (and gains) more experience to process 1M$ per day, every day, than it takes to process 40K$ per day.
In the first case an error is much more critical. I would pick any decent developer for writing the code if I had to process 40K$ a day. However if I had to process 1M$ I would probably pick the best developer I have.
So if code you have written is processing lots of money every day, then I can assume that you are quite experienced, otherwise they wouldn’t let you write that code in the first place.