where do developers spend their time?

Posted in programmer productivity at 1:05 pm by ducky

I read yet another paper by Andrew Ko, this one titled Information Needs in Collocated Software Development Teams and co-authored by Gina Venolia and Robert DeLine.

They collected a bunch of data by shadowing developers of various sorts and got about 25 hrs of data out of it. Mostly they were interested in what kinds of information people need and use, but as a side effect they also logged how much time was spent on what type of activity.

I was curious about how much time people spent on what activity, but they didn’t publish the breakdowns. I can completely understand that — the classification was probably subjective, the sample might have been skewed, blah blah blah. It wouldn’t have had much academic validity.

Still, it is interesting from a non-academic standpoint. It’s another piece of information that helps me create my model of the world. Thus I eyeballed times from a chart in the paper, and this my very imprecise view of how that group of non-randomly-selected developers spent their time:

  • 19% – understanding execution behavior (reading code, using the debugger, asking co-workers)
  • 18% – writing code
  • 15% – reproducing a failure (reading bug reports, setting up test machines, running code)
  • 13% – triaging bugs (thinking, talking with other developers)
  • 11% – reasoning about design e.g. what is this code supposed to do? (thinking, asking others)
  • 10% – non-work
  • 8% – maintaining awareness (reading bug reports, reading submission reports, reading email)
  • 6% – submitting a change (making sure submission was correct, diffing, running unit tests, using debuggers)

Note that they didn’t define what “non-work” meant. Did writing docs count as work? Did helping marketing out count as work? Did helping a teammate count?

While the numbers seem reasonable if I think about it, if you had asked me how much time was spent on submissions and on triaging bugs, I would have given much smaller numbers. That was surprising to me.

These numbers also show that what one learns in school — how to write a piece of code from scratch — is only a very small portion of what one spends time on in The Real World. While I hear a lot of angst from educators about “communication skills”, I have never seen a class on how to write a good bug report, or how to write a good submission report. I wouldn’t have ever heard of classes on how to write good email messages if I didn’t happen to be a recognized authority on that.

I also haven’t seen much training on how to use a debugger, how to reproduce bugs, or how to triage bugs. Maybe there isn’t much you can teach people on reproducing bugs or triaging them, but there certainly is a lot you can teach people about how to use a debugger.

NB: I was surprised to see that there were nine phone calls in the 25 hours of observation, three of which were work-related. I didn’t know anybody still made phone calls in 2006! I probably got about two work-related phone calls per year in the past four years, and my cell phone log shows that I only get about ten phone calls total per month. The bulk of my communication is email, IM, and SMS.

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