The Unexpected Skills Interviewers Look for in Whiteboard Coding Interviews

During my experience as an Interviewer for a tech company at Google, I've encountered candidates who struggle with even the most basic coding tasks. These interviews are designed not just to test technical skills, but also to assess problem-solving capabilities, adaptability, and interpersonal skills. In this article, I will explore the specific skills interviewers look for when they ask candidates to write code on a whiteboard or on a cloud documents engine, and the general expectations placed upon them.

Filtering Out Inadequate Candidates

One of the primary objectives of whiteboard coding interviews is to filter out candidates who cannot write even the most basic code. For instance, I observed a candidate who struggled to write a nested loop - a fundamental task that many developers take for granted. Such candidates are often eliminated early in the process, as their inability to perform basic coding tasks reflects poorly on their foundational skills and understanding.

Evaluating General Problem-Solving Skills

Beyond technical proficiency, interviewers are keen to assess candidates' general problem-solving skills. Companies like Google desire engineers who can swiftly adapt to new projects and deliver results, regardless of their background. The ability to solve problems presented to them and translate those solutions into code is highly valued. These capabilities indicate a candidate's aptitude for innovation, critical thinking, and quick learning, which are crucial for success in a rapidly evolving tech industry.

Testing Problem-Solving and Communication

Whiteboard coding interviews are designed to test several key skills. The ability to write useful code is only a part of what's being evaluated. Interviewers are interested in understanding how candidates approach problems, how they think, and how they handle criticism. They want to assess whether the candidates can communicate their ideas effectively, work collaboratively, and take constructive feedback positively.

Illustrative Example: A Junior Interviewer Mistake

Recall an interview experience where a more junior interviewer was assigned to evaluate me, seemingly accidentally. When I pointed out his misunderstanding of my answer, it highlighted a critical issue with whiteboard interviews: they can sometimes expose the biases and expectations of the interviewer. This incident made me reconsider conducting whiteboard interviews myself, as such sessions can easily reveal the interviewer's preconceived notions.

Goals of the Interview

During my interviews, the main goal was to delve deep into the interviewee's knowledge and test their propensity for providing honest answers. Too many candidates merely parrot the answers they think the interviewer wants to hear, rather than presenting genuine insights. Only about half of the questions I asked had a "right answer"; the questions often served more as a test of the candidate’s veracity and willingness to reveal their true understanding.

Conclusion

Whiteboard coding interviews are not a perfect process, and they do result in false negatives and false positives. However, due to their widespread use, it is reasonable to believe that these interviews do lead to good hiring practices at large tech companies. By thoroughly evaluating candidates' problem-solving skills, adaptability, communication, and technical proficiency, interviewers can identify the best candidates for their teams.