Short version: most reference checks are theater. You call a friend the candidate picked, ask soft questions, get warm answers, and learn nothing you did not already believe. A useful reference check is different. It targets the right people, asks questions that are hard to dodge, and pays close attention to what the reference does not say. For a first engineering hire, where one mistake sets you back months, the half hour you spend doing this well is the cheapest insurance you will buy.
I push founders to take references seriously precisely because they are tempted to skip them. By the time you are checking references you are emotionally committed, you want the hire to work, and the references the candidate handed you are pre-selected to agree. That is exactly why the default version is useless and why a slightly harder version is worth so much.
Most reference checks are theater
The standard call goes like this. You reach a former manager the candidate chose. You ask if they were good. The manager says yes, they were great, we were sad to lose them. You thank them and hang up. You have confirmed nothing, because nobody hands you a reference who will say the opposite, and your questions gave them an easy exit.
The problems are structural. The references are curated by the candidate. The questions invite yes or no answers that default to flattering. And you, the caller, are already sold, so you hear confirmation everywhere. To get signal you have to fix all three: change who you talk to, change what you ask, and change how you listen. None of that is hard, but it requires deciding that the reference check is a real filter and not a formality you perform after the decision is made.
The questions that get past the script
Specific, behavioral questions are hard to answer with empty praise, because they force the reference to either tell a real story or visibly stall. These are the ones I rely on.
What did this person actually own, and what changed because they were there? You are looking for concrete impact, not a list of responsibilities. A strong engineer leaves a mark someone can describe. If the reference cannot name what changed, that absence is the answer.
How did they behave when things got messy, a deadline slipped or a project went sideways? Anyone looks fine when the work is smooth. You are hiring for the bad weeks. The story they tell about a hard moment is worth more than every adjective about a good one.
Did they make the team better, or were they great in isolation? Your first engineer sets the bar for everyone you hire after them. Someone who lifts a team is worth far more than a brilliant lone wolf who leaves friction behind, and references will tell you which one this is if you ask plainly.
Would you hire them again, and for what kind of role? The hesitation before the answer is often more informative than the answer. And the second half, for what kind of role, surfaces honest caveats a blunt yes-or-no would bury. A reference who would rehire someone as an individual contributor but pointedly not as a lead has just told you something important.
What is one thing they were still working on when you knew them? Phrase the weakness question this way and you usually get a real answer, because it sounds developmental rather than damning. Everyone has something. A reference who insists on none is either not close enough to know or not being straight with you.
Reading the pauses
The content of a reference check matters less than you would expect. The texture matters more. Warmth is hard to fake, so listen for it. A reference who lights up and volunteers stories is telling you something real that no scripted answer conveys. A reference who is correct, brief, and clearly waiting for the call to end is also telling you something, and it is rarely good.
Pay attention to the gap between enthusiasm and specifics. Lavish praise with no concrete examples often means the relationship was thinner than claimed, or the reference is being polite about someone they did not rate. Listen for the careful hedge, the slight pause before would you hire them again, the pivot to talking about personality when you asked about delivery. These are not proof of anything on their own, but a pattern of them across two or three calls is a signal worth more than the words. The single most useful question to end on is open and quiet: is there anything I should have asked but didn't? Then stop talking. What people choose to fill that silence with is frequently the most honest thing in the whole conversation.
Who to call, and how to get past HR
The references a candidate gives you are the floor, not the ceiling. Call them, but also ask each reference who else worked closely with the person, and politely follow one of those threads. A backchannel reference the candidate did not curate is worth several that they did. Be respectful and discreet about it, especially if the candidate is still employed, but a warm introduction through your own network to someone who worked with them is the highest-signal call you can make.
When you reach a former manager, the most useful person to hear from, you will sometimes hit a company policy that only confirms dates of employment. Do not push the official channel. Find the individual instead, the actual former manager as a person rather than the HR department, and ask for a candid five minutes. Most people will give it. And weigh peers alongside managers. A manager saw the output. A peer saw how the person worked when no one senior was watching, and that view is often the more honest one. All of this is part of de-risking a hire that, as I argued in your first senior engineer is a bet, you are never going to make with certainty. If the stakes have you unsure whether you are even reading the signals right, that is a fair reason to book a call before you extend the offer.
Frequently asked questions
Are reference checks even worth it for engineers?
Yes, especially for a first or early engineering hire, where a mistake costs months. The default soft check is worthless, but a targeted one that asks behavioral questions and follows backchannels surfaces real signal cheaply. It is the last and cheapest filter before you commit, which is exactly why it is tempting and wrong to skip.
What is the single best reference check question?
End with an open one: is there anything I should have asked but didn't, and then stay silent. What the reference chooses to volunteer into that gap is often the most honest thing they say. For substance, ask what the person actually owned and what changed because they were there.
Should I call references the candidate didn't give me?
Carefully, yes. Candidate-supplied references are pre-selected to be positive. A backchannel reference reached through your own network, or suggested by another reference, gives you a view the candidate did not curate. Be discreet, particularly if they are still employed, but these calls carry the most signal.
How do I read a lukewarm reference?
Texture over text. Correct but brief, praise with no specifics, a pause before would you hire them again, a pivot from delivery to personality. One of these is noise. A pattern across two or three calls is a real signal. Trust the hesitation more than the words.