We have recently been working on a case for a California-based firm in which we are conducting a number of in-person interviews. In this particular case, we are interviewing individuals who may have some knowledge of a fraud involving upward of several hundred million dollars.

As my colleague and I were driving around the New York metro area (which has nine of the nation’s worst bottlenecks) and sitting in hours of horrible traffic, I got to thinking about the effectiveness of in-person interviews and whether they really bring more value to the client than telephone interviews do.

One hundred percent of the time, it is always preferable to conduct an interview in person. In a perfect world, you would call up the person of interest, set up an appointment for a specific place and time, meet the person in a neutral area, and conduct an interview with two investigators — one asking questions, the other taking notes.

Perfect worlds exist on television but not in reality.

Or at least not in mine.

In-Person (Doorstep) Interview

In our line of work, an in-person interview is what we like to describe as a doorstep interview, which is showing up at someone’s home or business unannounced to conduct an interview. It’s not the ideal situation, but a private investigator would utilize this tactic for a number of reasons.

First, you don’t want to give the person an opportunity to think too much about the reason why a private investigator is standing at the door asking questions or to wonder whether or not they should speak. It sounds a bit deceitful, but I assure you it’s not. The reality is that if given the choice, most people just don’t want to be involved, or they are afraid they might say the wrong thing. But despite what people may think of private investigators, my only interest is in the facts, good or bad; it doesn’t matter which side I am working for. My experience has been that the more time you give a person to sit and think about why they should speak, the less likely it is the person is going to want to talk.

Second, an in-person interview gives the person a level of comfort. You might think the opposite, that showing up unannounced at someone’s doorstep might freak the person out. But in my experience, quite the opposite is true. People are more comfortable putting a face to a name.

Building a rapport with a person is also critical to successfully interviewing the person, and you have a much better chance of quickly building rapport in person than you do over the phone. In about 95% of the cases that we work on, the person I am speaking to has absolutely no compelling reason to speak to me or cooperate, unlike when being questioned by the police (or other governmental authority) or other authoritative interview (employer/employee). My ability to build rapport and trust and provide a compelling reason why they should speak to me is critical to having a successful interview.

All things considered, a doorstep interview is the best way to handle any investigative interview, but the biggest problem is that it is enormously time- and resource-intense. And there is that possibility the person may not be home, which is just a total waste of time. Doing an interview at a person’s place of employment is not recommended unless absolutely necessary.

Also, technology has made the world much larger; so you may have to do in-person interviews in New York, California and France, which require either extensive travel time and resources or getting multiple investigative teams up to speed. [It’s always best to use one investigative team to do the interviews to avoid involving other investigative teams lacking institutional knowledge about the case].

In sum, in a perfect world, in-person interviews are ideal, especially in situations where a few key witnesses/individuals may make or break the case; but they are enormously time- and resource-intense.

Telephone Interviews

There are a number of advantages of conducting telephone interviews. First and foremost, it is much more efficient and less resource-intense. A private investigator can sit behind a desk, utilize proprietary databases to find telephone numbers of former employees or witnesses to an accident who have been found through discovery, social media or resume databases, and make phone calls from the comfort of his or her desk. An investigator can potentially make dozens if not hundreds of phone calls in a day and work through a long list of potential leads.

Telephone interviews have no bounds, so I can call people all around the country or the world. And I don’t need a second investigator, because I can easily take notes while conducting the interview, or in some cases, I might record the interview if I get the person’s permission — or if state laws allows, I may record the conversation without his or her knowledge.

(If you are looking for a digital voice recorder [affiliate link], Amazon has number of high quality voice recorders starting at around $25. If you want to record a conversation through your computer, Pamela for Skype [affiliate link] is a great tool that I have been using for years with great success.)

The reality of any investigation is that you never know who is going to be helpful to your investigation. It could be anyone, from the janitor to the secretary to the CEO. Or from the best friend to the eighteenth cousin, once removed.

Because it does not take nearly as much time and effort to contact people by telephone, my list of “people of interest” might expand to others on the periphery. Whereas when conducting an in-person interview, you don’t want to waste precious time and resources trying to interview someone who may have no helpful information, but calling that same person might take all of a few minutes.

Telephone interviews do have their disadvantages. First, fewer and fewer people are answering their phone these days, especially calls from blocked numbers or from numbers that they don’t recognize. It’s also getting harder and harder to identify good telephone numbers as well, which makes it challenging to get in touch with people in the first place.

It’s also a bit more difficult to establish a rapport, so you may not get as much information as you hope or want on your first interview, but you can combat that by following up with other telephone interviews or scheduling an in-person interview at a later date.

Telephone interviews are ideal in cases where you have the potential for a large pool of witnesses or leads, or cases where you are gathering information from a wide group of sources.

Which Is More Effective?

Nine times out of ten, I would tell a client to conduct telephone interviews first, and if any interviewees are particularly helpful/meaningful, I would follow up with an in-person interview to get a signed statement. The exception would be extremely sensitive or high-profile interviews of a short list of witnesses.

In my own personal experience and the experience of the group of investigators I spoke to, in-person and telephone interviews have about the same success rate with people willing to speak to you; so from that point of view, it’s a bit of a wash.

This should all be taken with a grain of salt, though. This is entirely based on the type of work that we do, which tends to float into the white collar world.

You can ask my friend Hal Humphreys of Find Investigations, who does a lot of criminal defense work, and he may tell you the opposite.

So What Is Better?

In the end, it really depends on the type of work and your (or your client’s) appetite for utilizing your time and resources. As investigators, we bill by the hour, so from a pure efficiency standpoint, I would typically recommend telephone interviews.

What say you?


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13 replies
  1. hal humphreys
    hal humphreys says:

    Portion of transcript from actual telephone interview:

    Investigator: I’m working with xxxxxxxxx. I would like to chat with you for a few minutes if that’s possible?

    Witness: Man, I’d just rather not get involved in it honestly.

    Investigator: Okay. I’m in town all day today, I could meet you anywhere that would be convenient for you.

    Witness: You didn’t hear what I said.

    Investigator: Yeah I did. I just hoped you might forget about it.

    Witness: No sir. [HANGS UP]

    • Brian Willingham
      Brian Willingham says:

      Ha! I’ve certainly heard that before. As another commentor pointed out, “situations always dictate tactics.” So for some situations, telephone interviews are just not going to work.

  2. Private detective Liverpool
    Private detective Liverpool says:

    This can also depend on the reasons behind the interview.
    With a willing witness I always find at their home address is a good place as they may have other paperwork to hand to look things up, confirm dates and times etc.
    I guess it comes down to experience and the type of interview.
    I also find that the investigator having local knowledge can also be helpful in judging the type of people that may live in an area, and whether they are likely to be willing to be interviewed or not. And then making a relevant approach.

    • Brian Willingham
      Brian Willingham says:

      I am not sure I agree about the approach of knowing what kind of people in the area. I think some people get caught in a trap of have some preconceived notion about what people will say or do, which is not a good starting position.

      • Sharpline Investigations, LLC
        Sharpline Investigations, LLC says:


        Great article and I’m always educating clients on when to use phone and in person interviews. I agree to an extent on knowing your demographics of where you’re interviews are taking place and that swaying your decision. We conduct numerous interviews on a daily basis for plaintiff personal injury attorneys and we absolutely have to take this into account. In lower income level areas or areas where crime is substantially higher and they have a negative image of law enforcement or an investigator in general, in person interviews have been very effective for us as opposed to telephone interviews. Based on my experience and utilizing both methods in a particular area, most people would not answer their phone or quickly hang up because they immediately relate the interview process with law enforcement.

        Also as an investigator and prior law enforcement officer, I prefer in person interviews as there is a lot more that goes into an interview than just their words. Body language is one of the biggest factors in conducting an effective interview and I can’t get that on the phone. Also it’s much harder for someone to tell you to pack sand face to face than it is on the phone. You also can’t build enough rapport over the phone to be able to put someone at the same level of ease as you could in person. We can also tell by reviewing our phone interviews compared to in person ones that they tend to sound much more at ease and willing to provide much more detailed information during an in person rather than over the phone.

        Our effectiveness comes from doing similar things as you such as calling first to screen the individual on whether they will be a good fit for a phone or in person interview. Initial phone calls are never made from blocked numbers and we do this first to see if they even answer. If they don’t we’re not leaving messages on the first go around. We don’t want someone who wouldn’t cooperate with an investigator to have an easy out by never calling back because they already know who’s looking for them. So we anticipate their call back and if not within a day or so we call again. Eventually it gets to the point after 2 or 3 calls where we will leave a message for that person because they could not be calling back simply because they are screening their own calls. All this as you said is going to be driven by your specific case type, the people you’re dealing with, objectives, etc. There are too many factors to weigh to be able to cookie cutter when you could use an in person vs phone interview. They each have their pros and cons. This is that toughest part for the client to understand when their first priority is resources.

        And on a side note going with two investigators also has a little more intimidating factor from a psychological perspective that plays in your favor. It helps fill that void where there is no obligation for them to speak to you as just a pi. It makes them think, well if I have two investigators here I probably should cooperate as this must be pretty serious.

  3. John C
    John C says:

    I agree with all the blocked calls and nobody ever answering the phone dilemma. You could give a witness a heads up by sending a letter/note Via US mail or other delivery service, indicating the need for a conversation and either leave your email, phone or return address in order to get a response. You also control exactly what you want to initially say depending on who your’e contacting.
    Didn’t know about the Pamela for Skype recorder. Thanks!

  4. Jim Clark
    Jim Clark says:

    Certainly there are advantages of one over the other. If resources allow I prefer in-person interviews as I can read body language as I ask my question and while they’re answering the question. This is lost over the phone, but you can discern speech pattern changes, pauses to questions, etc.

  5. Sharon Worcester
    Sharon Worcester says:

    Great information – as a fairly new investigator I have often wondered this. Thank you!

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