Does ignoring Robocalls make them stop?

Does ignoring robocalls make them stop? Here’s what we learned from getting 1.5 million calls on 66,000 phone lines

New research aims to give phone companies tools to help curb robocalls.
Peter Dazeley/The Image Bank via Getty Images

Sathvik Prasad, North Carolina State University and Bradley Reaves, North Carolina State University

The Research Brief is a short take about interesting academic work.

The big idea

More than 80% of robocalls come from fake numbers – and answering these calls or not has no effect on how many more you’ll get. Those are two key findings of an 11-month study into unsolicited phone calls that we conducted from February 2019 to January 2020.

To better understand how these unwanted callers operate, we monitored every phone call received to over 66,000 phone lines in our telephone security lab, the Robocall Observatory at North Carolina State University. We received 1.48 million unsolicited phone calls over the course of the study. Some of these calls we answered, while others we let ring. Contrary to popular wisdom, we found that answering calls makes no difference in the number of robocalls received by a phone number. The weekly volume of robocalls remained constant throughout the study.

As part of our study, we also developed the first method to identify robocalling campaigns responsible for a large number of these annoying, illegal and fraudulent robocalls. The main types of robocalling campaigns were about student loans, health insurance, Google business listings, general financial fraud, and a long-running Social Security scam.

Using these techniques, we learned that more than 80% of calls from an average robocalling campaign use fake or short-lived phone numbers to place their unwanted calls. Using these phone numbers, perpetrators deceive their victims and make it much more difficult to identify and prosecute unlawful robocallers.

We also saw that some fraudulent robocalling operations impersonated government agencies for many months without detection. They used messages in English and Mandarin and threatened the victims with dire consequences. These messages target vulnerable populations, including immigrants and seniors.

Why it matters

Providers can identify the true source of a call using a time-consuming, manual process called traceback. Today, there are too many robocalls for traceback to be a practical solution for every call. Our robocalling campaign identification technique is not just a powerful research tool. It can also be used by service providers to identify large-scale robocalling operations.

Using our methods, providers need to investigate only a small number of calls for each robocalling campaign. By targeting the source of abusive robocalls, service providers can block or shut down these operations and protect their subscribers from scams and unlawful telemarketing.

What still isn’t known

Providers are deploying a new technology called STIR/SHAKEN, which may prevent robocallers from spoofing their phone numbers. When deployed, it will simplify traceback for calls, but it won’t work for providers who use older technology. Robocallers also quickly adapt to new situations, so they may find a way around STIR/SHAKEN.

No one knows how robocallers interact with their victims and how often they change their strategies. For example, a rising number of robocalls and scammers are now using COVID-19 as a premise to defraud people.

What’s next

Over the coming years, we will continue our research on robocalls. We will study whether STIR/SHAKEN reduces robocalls. We’re also developing techniques to better identify, understand, and help providers and law enforcement target robocalling operations.The Conversation

Sathvik Prasad, PhD Student, Department of Computer Science, North Carolina State University and Bradley Reaves, Assistant Professor of Computer Science, North Carolina State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.


7 Responses to Does ignoring Robocalls make them stop?

  1. anonemoose February 24, 2021 at 7:19 am #

    I have used two methods to stop unwanted calls that have worked. First one; I recorded the phone company’s “beep,bop,ding, the number you have reached is not longer in service and there is no new number” message and used it for my voice mail message.Told all the people that mattered that there was a fake message on the machine just wait and leave a message. At the time the robocaller systems would recognize the three tones and hang up. Now I use a one second of silence for the voice mail message and they seem to think the call was dropped or didn’t go through and hang up. I do get some funny comments to listen to though.

    • Sweet! February 24, 2021 at 8:02 pm #

      Love those ideas! Thanks for sharing.
      I once had my own name and number show up on caller ID on my landline. I almost answered that one, just in case I was calling myself from a parallel universe. But then I realized that if I was a scamming telemarketer in that parallel universe, I’d rather not know about it.

  2. Jacqi February 21, 2021 at 7:29 am #

    I never answer an unknown number anymore. Leave a message. Most robocalls don’t. Then I block those numbers. Also my phone only “rings” for Contacts..

  3. Rick O'Brien February 20, 2021 at 10:26 pm #

    Whenever I list something for sale on Craigslist , my first call (within 2 or 3 minutes) is always from Nigeria AND , offer to over-pay for the item . Go figure…

  4. Charlie Rader February 19, 2021 at 7:20 pm #

    Recently I have observed a strange combination of clever and stupid by robocalls. The caller will spoof a phone number, like a well known bank or an automobile company, shown by my caller ID. But when I answer the phone, the recorded preliminary says that they are Social Security, or can reduce the interest on my credit card. Whatever scam they are running, it would seem to require that I trust the caller, and since I can tell that they are spoofing the caller ID, why would I ever trust him?

  5. Rick O'Brien February 19, 2021 at 12:03 am #

    When I get a call from an area code that is not located in the US , I BLOCK it . That might not do much, but it gives me a certain amount of satisfaction knowing they can’t call again .

  6. Frankly Speaking, it's out of control February 18, 2021 at 10:13 pm #

    Well, that’s depressing. We cannot answer our phones without being worried about being scammed. To hear that not answering these calls has no impact on the number of them is discouraging. And that it’s happening on both landlines and our cellphones is especially discouraging.

    Computer software programs have reduced our ability to control our personal information and how we live our lives. There are important phone calls that all of us receive from family, friends, doctors, coworkers, and service repair people; the list goes on and on. We should be able to trust the main link we have between us, our phones, to communicate. It should be illegal to spoof phone numbers. And there should be consequences that make those engaged in this type of activity think twice before engaging in it. It’s going to take cooperative agreements with other countries to effectively pull it off, but it’s worth at least the effort.


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