In our process, we use almost the simplest possible tasks like making an HTTP request to our API and displaying the data im some form and ask people to solve them 'just as they would as part of a project they are working on'.
They get a timeframe and have to quickly elaborate on their process, what they got done and what they didn't get done.
There are drastic differences between candidates. Some barely manage the task or are satisfied as soon as it works. Some over engineer to no end and reason about all the bells and whistles and others write abstracted code without overdoing it, add some tests and rudimentary docs.
The way people approach this simple task and what their threshold for 'solving' it is has told me more about people than any difficult interview question.
Not that easy! A valid technical test needs to be custom made for the position and project (or type of project) you hire for and takes a while to both prepare and “grade”. It also then helps in giving you something very specific to talk about at the interview (I always find something to talk about when reviewing the code they submit for the test).
It still won’t have a 100% success rate, the best you can do is hire people you/someone you trust in the team have worked with before and know is good.
