I think the question whether this is fair or not is misleading. If you are interviewing a candidate the job is to hire the best person for the position you can find. A candidate which cannot answer a simple question about affine transformation is definitely not the strongest candidate. I run into the same issue with white board coding interviews all the time. People claim it is unfair and doesn't bring out their strengths. I agree with all of this, but in my opinion a false positive is more expansive for a company than a false negative and as I know for sure that there are people exceeding at white board interviews and I am pretty sure that there are junior candidates that will be able to answer simple questions about affine transformation. These are the people you are looking for and the job of the interviewer is to find the best candidate. Personal drama has no room here.

So, in my opinion this was the right decision as there a potentially better candidates which are a better fit for that role and it is very legit to aim for this. Also, failing in an interview is not the end of the world. It happened to me as well! The important thing for the candidate is that he receives feedback and can take something out of the interview. So the next time he is asked about affine transformation he will be able to give good answers.

I agree with all of this, but in my opinion a false positive is more expansive for a company than a false negative and as I know for sure that there are people exceeding at white board interviews and I am pretty sure that there are junior candidates that will be able to answer simple questions about affine transformation. These are the people you are looking for and the job of the interviewer is to find the best candidate. Personal drama has no room here.

Especially for a junior position, I'd be far more interested in the candidate's thirst for knowledge, personal growth, the way they approach problems and their social/communication skills.

Especially for a junior position, I'd be far more interested in the candidate's thirst for knowledge, personal growth, the way they approach problems and their social/communication skills.

All true, but I am surprised how someone with these traits would not know about affine transformations when applying for a role as game developer. I did practice with people from DigiPen at the whiteboard here at the office and also did go for many lunches to answer their questions. One of the guys just landed a senior position at Amazon essentially after a couple of months out of college. This is what I compare this junior candidate against and this is a guy with dedication and good social skills. There is competition there and there are excellent people out there at all kind of levels.

The point I want to make is not to only see this from the perspective of a candidate, but also from the position of the interviewer. As the interviewer you need to get the best person out of the pool of people applying for the role.

There are many unknowns here. If there's literally only one role and you know you have other candidates are good, then sure, you might reject them based on one single question if you felt it was a super important one. But for many roles, it's not a really important question. And in many studios, you're not just hiring one position, you're hiring anyone that is good enough and paying them commensurately. So I still find the idea of rejecting a junior entirely because they didn't answer that question to be odd.

There was probably a time back in university when I could explain in detail what every part of the matrix meant and all these other details, but I've been in the industry a decade and I can't remember that stuff now because it doesn't matter. I don't think I've heard the term homogeneous transformation matrix for years except for this thread. It doesn't come up in practice because most of us can just use whatever functionality the engine provides to build and manipulate the matrices. e.g. If I need one in UE4, boom, FRotationTranslationMatrix::Make to the rescue. Like Hodgman said, the matrix can essentially be a black box unless you want to dig a bit deeper. Personally, I've always seen far too many people getting bogged down on rendering minutiae while neglecting gameplay, networking, and AI, so I specialised in those instead. No regrets.

Thanks everyone. Haven't been ghosting this thread, but really wanted to see different opinions before making my mind about it.

I'm afraid that, I too lack pieces of the puzzle and really can't rule one way or the other (and admittedly, this is less about trying to guess whether it's black or white than to gauge the shades of grey).

I do agree with several views shared here:

• Whether it's 'fair' from the recruitment perspective is hardly relevant: recruiters are in for the best candidate, and if they had already met someone better, it was a criteria just as good as any to cutting the interview short as they had 'heard enough' (I can only assume earlier questions built up to that moment, even though they were not explicitly referred to).

• There may have been unspoken requirements which may have impacted applicants negatively. I can remember a similar case where I had personally applied for a job about half a decade ago, and I was exceeding every requirement listed on the job ad by a wide margin, just to get on the 2 minutes call with the recruiter who looked up my resume and asked me 3 questions before saying: 'you're not nearly experienced enough' and, 'your resumé is not detailed enough, I should've known you hadn't done X before' (which the ad did not specify as a requirement to begin with, and objectively was not an information that could've been inferred without knowing the actual (confidential) projects the organization was taking on).

• Authoring tools and 'friendly engines' such as Unity have made development more accessible to a lot of people, but in so doing have also contributed to the dilution of low-level developers that understand what happens behind the scene, making the 'real coder' a much rarer find. Similar to a post-apocalypse where no one could build anything without a power drill or even replicate any form of AC/DC converter for said tool, it feels like an organization is weakened by potential threats (changing techs for example).

The bottom line is that it's likely fair that the candidate didn't get the job, but that it wasn't necessarily 'his fault' in that he had no indication prior to the interview that his skillset did not match the requirements, and that, I believe can be attributed to unclear requirements from the recruiter, which is unfortunately all too commonplace where job ads are written in silos with next to no communication with devs.

Thinking back, I can distinctly remember a recruiter at a studio I worked in that had created an advert calling for Unity developers familiar with either C++, JAVA or Python... I mean, really? JAVA != Javascript && C++ != C#, lady! At least we caught this one on time...

Thanks again for all the valuable insight!