Let us get the facts right first
As everyone else, as soon as I entered the professional scene, getting paid for work, I encountered interviews. I was interviewed on multiple occasions. I passed some interviews, failed others. I accepted some job offers, declined others. I am guessing that everyone has similar experiences.
Since 2010, I got involved in other side of an interview process. Instead of being interviewed, I did interviews. I did interviews in many companies, for all kind of positions, and I did all parts of interviewing process over the time. I interviewed a large number of people from all over the world, and I spend much more time in "driving seat" instead of being interviewed.
As far as I see, a lot of people, even experienced ones, are still struggling with the understanding of interview process, and why even if someone is the right person for the job, they don't pass the interview and get the job, so I wanted to share my view on it.
Although Interview process is different from company to company, core things are the same for all of them.
It all starts with an open position that needs to be filled in. Someone will come with requirements according to which opening will be announced. CV's will be gathered and filtered according to job specification and some other criteria. CV's will be ranked and top X of them will "pass" this part and will advance in an interview process to the next stage.
Sometimes there will be online tests, or phone interviews or combination before reaching face to face, or candidates will be called directly for face to face. Again depending on the company, there can be 1 or more face to face interviews, after which final decision will be made about offering the job to the person or saying thank you, however we found a better candidate or something along those lines.
I am stunned by the fact how much people overlook how important small things are in their CV. Someone will look at "all" CV's and do simple filtering who should go to the next round and who shouldn't. In 99% of the cases, you will not be the only person who applied.
So first step is always filtering process removing does how are obviously not for that position, and then "ranking" them after which only top X will go to the next round.
No matter what the process is, at this stage no one knows who you are or how good and awesome you might be. The only thing they will have in front of them is your CV. And here small things do matter. Put your self in their shoos and think what would be their impression of someone only according to CV. Here are the things that will put you in front of others in most cases
Different things will have different weight, but all the above will definitely put you in front of someone else, who is same as you but don't have one of those things that you have.
Bottom line is that not everyone will get the shoot at next part of an interview and you need to be in top X to get that chance.
Doing interviews is very time consuming, anyone saying different is either lying or not doing it in the right way.
This is also the reason why only top X people will go from one phase to next phase.
It is taking time from the person being interviewed, but also the one who is doing the interview. Due to time constraints and similar, there will be a very limited amount of time in which you will have a chance to show why you are the right person for the job and person on other side will try to evaluate if you are the right person or not. In most cases, time given for an interview will not be enough to do this complete justice.
In case you are an obvious miss or hit for the job at hand it should be sufficient, however in all other cases and especially if a number of positions available are limited it will be a different game. Since now, not only interviewer need to evaluate if you are right for the job or not, but also need to rank you compared to other candidates.
Due to limited time, you will spend with interviewer do your homework, find info about the company, about the position, prepare questions that you want to ask. Also, think in advance about their questions. More things you do beforehand, easier it will be during the interview process.
Interview process differs from day to day work. Time constraint is different, limitations are different, problems at hand are different, the way you interact with people is usually different.
I know a lot of great engineers who failed interviews they should ace, just because they were not prepared good, or didn't refresh knowledge on somethings. Here it is also very important what type of questions are asked, and what type of knowledge/skill is looked at.
Do your homework as much as you can, and prepare as much as you can. Make sure to have all "advantages" that you can, or you can just miss getting that awesome job because of some small thing that could be fixed if you just prepare and practice little more.
Only in the case when it is obvious that you are not the right person for the job this isn't the case, in all others, this is the case.
A lot of things can play a role in you getting the job or not, going to next phase or not. Did you sleep well last night, do you feel good, did interviewer had enough sleep or feels good, family situation, current work situation for both you and interviewers, and a lot of other things.
I know people who passed. bt shouldn't since they were asked things they "knew" and they sucked at work, and also people which rocked at work, but failed interviews at that company first time they were interviewed.
The interview process isn't 0 or 1, it isn't black or white. It is in most cases some type of gray and depending on a lot of things that can't be controlled in the end it will be looked at as white or black.
There is always a certain amount of luck involved.
Knowing people in that company helps, but it doesn't mean that it will lead you to the job.
Being referred by someone inside company helps, especially with deciding who to put in top X who will go into next phase. Depending from a company to a company this might have more or less weight, also depending who did a referral. The only guaranty that you will get is that someone will take a closer look at your CV, nothing more can't be guaranteed.
Again, this will vary from a company to a company, but it helps for sure in case of all companies.
The interview process shouldn't be personal and should be as objective as possible. This also depends from persons doing the interview, and if they didn't do all that was needed in order to make it nonpersonal, they probably shouldn't be involved in the interview process.
On another hand, also don't take it personally if you are being interviewed. If you passed or didn't pass don't take it as clear indication who you are, what you know and don't know. The interview process is complex and long one, and luck is also involved and many other things. I know people who passed interviews but shouldn't, also I know people who didn't but should.
Doing interview isn't easy and some companies are better at making it objective, while in others it varies a lot depending on an interviewer.
Being good and objective interviewer is a skill that not everyone can master, and I meet a fair share of people doing interviews that shouldn't be doing them, both while doing interviews with them or being interviewed by them.