It was interesting to be placed in the situation of "I'm not happy witht the quality of the code that is being written by the developers. There are far too many bugs being logged". As the development team leader of a small team working on a production app, which the team is giving their all for, my immediate reaction was "You gotta be kidding!". After a brief protest, I decided to stop there, not do any putting-of-foot-in-mouth, and have a good read up on any stats available (although I was damn sure 1 to 3 errors per 100 lines of code was average in our industry).
UPDATE: 2008 NOV 25 - Updated link
I found an interesting article at http://panko.shidler.hawaii.edu/HumanErr/ProgNorm.htm which has summary stats on numerous projects dating from the mid-70's to now.
The summary of it was as follows:
- 32 Projects with usable stats
- Max Error Rate: 25%
- Min Error Rate: 1.1%
- Std Dev: 0.046
- Average: 4.1%
- Average Dev: 0.0275
My interpretation of this is, based on 32 seperate projects, an average error rate of 4.1 lines of code per 100 became evident. Taking the average deviation from the mean, which is 0.0275, that indicates a range of 1.35% to 6.85%.
Some other intersting points that I noted, although not necessarily worth pondering on, was that the coding rate averages about 120 - 150 lines per hour.
That's it - please feel free to add your info to this.
UPD 2007JUN21: Lost my DB and changed ISP's - sorry I lost everyones comments