Coding interviews are administered by companies as a proxy for the future job performance of software engineering candidates. However, it is highly uncommon for a software engineer to be writing tree traversals and graph algorithms from scratch on the day job. The day job focuses more on correct business logic, good software design, and clean code with often incremental additions and improvements. So, are coding interviews a good proxy for job performance? My answer is still "yes".
First, the coding interviews are deeply testing the project management and execution skills, which are the core to any software job. Preparation to the coding interviews is a project, which needs to be handled with care. The topics covered by the project: how to learn and practice the set of coding problems per company, how to gain a working knowledge of fundamentals and a muscle memory on how to apply them, how to be efficient with practice and review, and how to be consistent in your efforts. Great execution of this project invariably leads to stellar interview performance and shows that you can get things done.
Secondly, there are the elements of clean code and good software design, showcased and judged in the coding interviews. Executing the preparation project well often gives a candidate the confidence and the extra time to write clean well-encapsulated code. Doing these always impresses both your interviewer and your code reviewers on the day job: separating constants, splitting lines, splitting independent pieces of logic into their own methods, proper method naming.
In third, a new wave of coding interview practices and tools (e.g. CoderPad.io) encourages reaching correct business logic, which tests the debugging skills. Debugging is a critical part of a coder's day job. Almost all companies in 2023 (apart from Google) want you to run your code and pass a basic set of test cases. It is very important to learn to quickly reverse engineer from an observed failure to a bug in your business logic, especially on the day job.
Fourth, software engineering is a team effort with collaboration and communication skills being as important as coding itself. Those soft skills are easily assessed during the interview. A structured approach of writing down the functional requirements, checking your algorithm against interviewer's expectations, and discussing the implementation waypoints + the tradeoffs show, especially for the senior candidates, their clarity of thought, flexibility, stakeholder communication, and mentorship skills. You need to be great to work with.
So much to unpack! Did the text make you rethink your preparation strategy? Please, leave your thoughts in the comments.