Interviewing Developers

Joel Spolsky writes a very interesting guide (The Guerrilla Guide to Interviewing (version 3.0)) on how to interview candidates properly to find out the best hire for a developer position. I've only recently been able to test applicants for our company but only as a peer level test. I haven't interviewed any of them other than viewed their resumes and the results of the interviews of managers.

Most of the candidates failed the Java and SQL proficiency tests but our company is desperate so I made up some small problems for them to try and solve. I made them write a program that would use a loop to display the following:

*
**
***
****
*****

I then asked them to rewrite that loop to display:

*****
 ****
  ***
   **
    *

Next, they were asked to take the last triangle and count the number of asterisks per line. Lastly, they were asked to sort the number of asterisks into ascending order.

I'm very surprised that no one was able to ace the exam and only two had some competent solutions to the first and third problems. Those two might have just been copying each other's work.

We ended up hiring one of the two who were able to answer some of the test. I'm hoping it's not a bad decision.