Research shows answering one robocall doesn't lead to more

One study used 66,000 fake phone lines to debunk robocall myths.

Rafael Abdrakhmanov via Getty Images

In an attempt to better understand robocalls, researchers from North Carolina State University set up 66,606 fake phone lines and recorded 1,481,201 unsolicited calls over an 11-month period. Their research debunks a couple longstanding myths, but it also confirms that if your number is spoofed, you may be in for a robocall “storm.”

While it may feel like robocalls are becoming more frequent, the NC State research suggests that the number of robocalls has remained flat from month to month. The team also found that answering a robocall does not make you more likely to receive other spam calls.

But those stories about people being bombarded with so many calls from unknown numbers that they can’t use their phones are likely true. The researchers found that, when a robocaller masks itself with a spoofed phone number and makes hundreds of thousands of calls, many of those recipients will call the number back.

“The high volume of calls essentially makes it impossible for the person who actually has the relevant phone number to use their phone,” Brad Reaves, co-author of a paper on the work and an assistant professor of computer science at NC State, said in a statement. “However, because robocallers switch numbers fairly often, the inconvenience usually only lasts for a day or two.”

More importantly, the team was able to group some of the robocalls into clusters stemming from 2,687 specific campaigns. Most campaigns only made a few calls, but some placed thousands of calls.

“Effectively you can narrow down a big chunk of robocalls to only a few campaigns. And you can track those down. That’s a subject we’ll be discussing at greater length in the future,” Reaves said.

If investigators are able to track thousands of calls back to just a handful of campaigns, they may be able to better fight spammers. Hopefully, that, coupled with FCC fines, call authentication, international robocall tracing, commercial spam blockers and other efforts, might actually solve the robocall issue.

As NC State points out, robocalls are not just a nuisance or a security threat.

“The COVID-19 pandemic has really highlighted the importance of this work, because robocalls have made people less likely to answer phone calls from unknown numbers — and that makes it more difficult for contact tracers to do their jobs,” said Sathvik Prasad, a NC State PhD student and first author of the paper.