The standard software engineering interview involves 3 to 4 technical interviews lasting 45 minutes to 1 hour each. What always confused me is that these interviews are generally done with marker on a whiteboard. It’s 2019, we have options. Those options are solutions like Coderpad, basically a screen-shared REPL (read-evaluate-print loop).
Typing speed is 5-6x faster than writing speed
The average typing speed is 75 words per minute. The average writing speed is 13 words per minute. Slower transcription speeds means less information can be conveyed per unit time.
Whiteboarding is space constrained
You can only write so much on a whiteboard. If you aren’t tactical about how you approach whiteboarding (e.g. small writing, good placement of functions), you can run out of space. If you are forced to erase prior work, but later realize it needs revision, you must re-write it. Combined with slow transcription speeds, this will cost precious time and attention.
Typing allows flexible edits
The largest pain point of whiteboarding is making edits. If you have to make an edit in the middle of a line, what you write may not fit. You may be forced to erase previous lines you wrote to make new space for something you forgot. Combined with slow transcription speed, you are doubly penalized if you make a mistake that involves erasing prior work.
Typing never has this problem. Text within a line is offset as you type new characters or newlines. You can copy-paste if need be. Your attention can be directed more fully on the problem rather than tactical placement of functions and expressions just-in-case.
Coderpad iterations are faster
Writing on a whiteboard means you must check for errors manually by walking through the code with simple examples. This is a slow, error prone process and naturally takes up a lot of time in an interview where time is naturally scarce.
With coderpad, you can immediately know whether your solution works for your test cases allowing you iterate faster.
Conclusion: Coderpad allows for more information density than whiteboarding
There’s really no getting around the fact that you can do more in a Coderpad-style interview than with a whiteboard. You can transcribe information faster, edit information faster, and iterate faster. There are only two reasons I can think of where whiteboarding would have a serious advantage:
- Whiteboarding will never have technical/IT issues. Whiteboards never fail. Markers are usually redundant.
- Whiteboarding has network effects. This basically makes whiteboarding the QWERTY of interview media.
To me the advantages of whiteboarding are not compelling. Whiteboarding limits the ability of the candidate to translate their ideas into code relative to Coderpad-style interviews and unavoidably filters candidates by an unpractical skill (tactical whiteboarding). Even a text-editor would be strongly preferable to whiteboarding.