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6 Ways to Conduct a Backdoor Reference Check

6 Ways to Conduct a Backdoor Reference Check

“Deep reference checks”, “informal checks”, or “background checks” tend to generate a bit of controversy on the recruitment scene, but are still widely used, particularly for higher executive roles.

A backdoor reference check refers to obtaining information about a candidate from a source other than those referees specifically listed on the candidate’s resumé. It used to be that reference checks were the only way of determining a future employee’s personality and past experience levels based on conversations with previous supervisors.

With the advent of social media and web footprints, it’s now easier than ever to get an idea of the real candidate behind their CV.

Reference Checking Template: This guide will provide you with all the tools you need to run consistent reference checks every time and validate the information provided by the candidate at interview. Download Now!

Why would you want to conduct a backdoor reference check?

Backdoor reference checks are particularly useful to assess two things: a candidate’s personal traits and their past performance.

Are they really as good as they make out or are they just good at interviewing?

It’s crucial that a hiring manager can get to the bottom of someone’s background and work performance before bringing them on board. You don’t have to search very far to come across a story where it has become apparent that a new employee has only known half of what they said they did.

But are they illegal?

It is not illegal to get an opinion from someone connected to a candidate, however there are particular practices to avoid. If you’re a recruiter, you will probably have a legal responsibility to your clients that are best met by ensuring you conduct (typically two) thorough reference checks. Placing someone in a position without confirming his or her previous work history could get you in trouble for negligence, misrepresentation, or even conspiracy of fraud.

Let’s just say it’s not pleasant when a client calls you and says, “We’ve just had to let Stanley go today. By the way did you know he was let go from his last role for embezzlement?


There are many ways you can go about finding out more about your candidate than by simply speaking to the referees listed on their resumé. Here are our favourites:

1. LinkedIn

The easiest way to begin is with a LinkedIn search and seeing what connections you might have in common with the candidate.

Depending on your level of connection, these are the first points of call to discover more about a particular candidate. It’s possible the people they know on LinkedIn may never have worked with them so don’t just immediately call your common connection and ask for information. Rather, check their background and look for people who might have deeper professional / career related information.

Many people now have recommendations or endorsements on their LinkedIn profiles. Even if you don’t have any personal connection with them, it’s not unusual to attempt to contact these people for a phone conversation. If they’ve already agreed to write a recommendation once, they’re unlikely to find it unusual for someone to call looking for verbal confirmation.

In fact by providing a testimonial for anybody on LinkedIn you’re basically putting yourself out there to be contacted as part of the reference checking process. It’s unlikely someone will give an all out bad reference, so if you get an opportunity to hear their voice you can better ascertain their enthusiasm for recommending that person.

2. Social Media

We’ve talked about the power of social media in getting a better understanding of a potential employee previously.

Rather than looking for information on a person, this time you’re looking for people they are connected to. For example do they have a lot of conversation back and forth with someone on Twitter? Are they connected to someone you know on Facebook? Are they a regular follower or commentator on someone’s blog?

3. Google Search / Websites

Many people have a personal blog or online community they are a part of. These sites can give you a host of information on the person as well as providing potential points of connection. If they’re active in a community, contact the founder of the community or group to confirm their involvement.

4. Alumni Groups

Alumni groups are an excellent source of secondary information about an individual. A person’s reputation within their college, especially if they graduated recently, will say a lot about them as an individual. Look for alumni they may have worked on projects with or are still in contact with. You can get information about alumni groups from LinkedIn, University websites, or Facebook.

5. Face-to-Face Meetings

Particularly if you operate in a specialised field in a particular location, there’s often only 2 or 3 degrees of separation between you and anybody with a worthwhile opinion. Setting up a coffee is the best way to get in-depth information on someone. Face-to-face allows you to read body language and initial reactions, which can tell you a lot about a candidates’ true experience with that person.

6. Other Connections

When calling the referees provided by the candidate, don’t forget to ask, ‘Who else worked with <candidate> that I might be able to talk to?’ This will likely bring up a host of people that are quality sources of information because they’re from someone your candidate already recommended. Perhaps the person you’re talking to is too close to the candidate to be fully honest – but they’re more than happy to put you in touch with someone else who can!

Here are a few other pro-tips for conducting backdoor reference checks:

  1. Get blanket permission from your candidate to get reference checks on them. This is standard practice and must be in writing (email is ok).
  2. Never contact anyone at the candidate’s current place of employment unless they have explicitly specified that it is OK. You don’t want to be responsible for letting the cat out of the bag that they are looking for a new role.
  3. Ensure the person is a credible reference source, and take their words with a grain of salt. There are many reasons for a bad reference check: personality clashes, cultural clashes, and micromanaging can all leave a bad taste in someone’s mouth.
  4. Assume that the person you contact will get back to the candidate. We actually experienced this directly, when one of the most valuable backdoor checks we performed turned around and called our candidate to let her know we had called within about 15 minutes.
  5. If you’re a recruiter, only pass on to your client information that would also be happy to pass on your candidate. It is illegal to pass information you have gathered about a candidate to an employer and then refuse to give the same information to your candidate. This helps to avoid situations where a candidate is rejected but they are unable to find out why.

What methods have you used to get the ‘real story’ behind a potential candidate? Any favourites? We’d love to hear them!

Cofounder at RecruitLoop. I've been a hands on recruiter, manager, trainer, coach, mentor, and regular speaker for the recruitment industry for 20 years. Follow me @paul_slezak.

  • Sarah Clark Stuart


    Is there standard way to ask for “blanket permission” to get reference checks from my candidate? I’m a little unsure how to phrase it in an email.


    • Paul Slezak

      A good way to handle it is to firstly ask the candidate to provide you with the details of specific referees. But to then explain that part of your process is to also reach out to other connections and to then add something like “so hopefully you’ve got nothing to hide if I were to reach out to any of our mutual connections on LinkedIn”.

  • Toby Clarence-Smith

    Putting aside ethical issues, is it actually illegal to do a backdoor reference check without “blanket permission”? And if so, why is that? If Im hiring a nanny for my children, seems fairly reasonable that Id want to be very thorough in my reference checking, despite whether the candidate wants me to do so or not. I dont see why it should be any different for a more “normal” position