Sunday, June 30, 2013

Technical Interviews: The Missing Piece

Typical Interview Question: Write a Java method to reverse a string.
TechCrunch had a recent piece about the demise of the technical interview. In software engineering, the technical interview involves writing code. Companies like Amazon and Google have a reputation for asking brain-teasers such as, "How many gas stations are in the US?" or "How many Ping-Pong balls can you stuff into a Boeing 747?" The idea is to see the job candidate's thought process. While these questions are mentally challenging, it's probably not the best indication of how good the candidate is at programming.

I've been through a number of software engineering job interviews where I've been asked to write code and discuss fundamental computer science questions. Writing code is an important part of hiring software engineers and it definitely has its place in the job interview process. And, it's perfectly okay for the candidate to make typos or have syntax errors when writing computer code on a white board. The idea is to see if the candidate understands the fundamentals of computer science such as Big O notation when it comes to a binary tree [O(log n)] or hash table [O(1)] or the basics of recursion and language syntax.

The Missing Piece
One thing I've noticed missing from all my job interviews over the past 15 years is that no one has ever asked me to show code that I've already written, refactored, and trusted for many years. The beauty about reusing code that either I or someone else has previously written is that code you don't have to write is code that you don't have to debug.

Software engineers who live for and love writing computer code have many side projects. You'd be hard pressed to find a good software engineer who doesn't have something currently deployed whether it's a web application or smart phone app. Just like an artist has to paint, or a poet has to write – regardless if they're paid or not – a coder has to code.

The Alternative
The current software engineering interview at a decent tech company involves a series of 45 – 50 minute long interviews where a pair of employees ask the job candidate questions. This process can last four to six hours and the key part that's missing, today, is where the job candidate gets to show off what they've previously written and released. This is especially important for a 40+ year old job candidate who should have a massive bag of tricks since they've probably been coding, on a daily basis, for more than a quarter of a century.

Instead of multiple 45 minute interviews with two employees and a job candidate, it would be much more effective to have a couple 90 minute interviews with four employees where the candidate can show how they architected, coded, and deployed a website or smart phone app. Ideally, the candidate could ssh into their live servers to show the details, challenges, and architecture of how a web app works while showing off the code that he/she has written to accomplish it. Writing code on a white board is very academic; seeing code that a candidate has deployed and maintained over several years is about as real as it gets.

No company would hire a graphic designer without seeing the job candidate's portfolio so why don't tech companies demand the same thing from software engineers?


Brito said...

Very good perspective. I wish more interviewers would indeed have the boldness to do this kind of thing. I guess that in most cases they just pass through too many applicants and the attention span is reduced to standardized approaches.

Joe Moreno said...

Thanks, Nuno – glad that you like my perspective. I really think career software engineers should show up to job interviews with a portfolio.