A data-driven approach to spam area codes: why the most common advice is mostly wrong

Do some area codes scream “spam” to you? Do you think that simply not picking up calls starting with 347 for New York City will protect you from phone scams? Think again. The latest data from the Federal Trade Commission (FTC) paints a very different picture. It turns out 59.81% of all unwanted calls are local calls originating from the same state. Or at least they appear as such.

Incogni’s research team analyzed FTC data and found no evidence of the existence of any specific area codes to avoid in order to stop spam. With no specific numbers to point the finger at, what should new spam prevention guidelines look like? And what is the role of data protection in the prevention of future spam?

Key findings

  • Most recommendations on how to avoid spam provide misleading information, highlighting specific spam area codes to avoid across the US. Data shows that spam area codes differ for each state. 
  • Almost two out of three spam calls (59.81%) are made from a local number originating in the state in which the receiver lives (or at least it appears so as the number could be spoofed). 
  • With the exception of toll-free numbers, very few spam area codes are reported in more than one state.

Be aware of popular advice

The internet is awash with recommendations on spam call prevention, and most sources indicate specific area codes to avoid. These are called spam area codes, and many reputable sources publish lists of them along with other preventive recommendations. Almost all anti-phone-spam guides repeat the same area codes as potential offenders⁴ with area code 216: Cleveland, Ohio at the top of the list, followed closely by 469: Dallas, Texas, and 657: La Palma, California. 

Yet, according to the data published by the Federal Trade Commission, there is no evidence that any of these area codes dominates the list of unwanted calls. What’s more, spam area codes reported to the FTC are substantially different from state to state.

There is no one country-level list: “spam” area codes are different for each state

Incogni’s research team analyzed the ten most frequently reported area codes in each state to identify whether any of these codes are common across multiple states.

With rare exceptions, the top ten most frequently reported spam area codes vary considerably between states. For instance, the top ten spam area codes for California and Colorado are entirely different.

However, toll-free numbers starting with 833, 888, 855, 800, 866, and 844 are common across the entire country, affecting all US residents irrespective of state boundaries. It’s reasonable to caution against these in all publications on spam area codes.

Most spam calls originate from a local area code

The data published by the FTC indicate that spammers use different area code numbers to target different states. Which spam codes are most frequently reported in each state? The surprising truth is that the overwhelming majority of all unwanted calls reported to the FTC come from the state in which the recipient of the call lives.

If we take the example of California, which reports the most unwanted calls overall, all top-ten numbers customers complain about start with a Californian area code. Texas, whose residents report receiving the second-most unwanted calls, also reports local codes most frequently. In fact, the same is true for the majority of all unwanted calls reported across all states. 

Top ten reported spam calls area codes per state

To gain insight into how often residents of a given state are targeted by spam calls originating from that state, Incogni’s researchers analyzed the numbers of all reported calls by state. The results show that most states receive spam calls that appear to come from within their own  state lines. 44 out of the 50 states on which the FTC has data report the majority (over 50%) of unwanted calls originating from within the state. On average, across all US states, 59.81% of all unwanted calls reported to the FTC are same-state calls.

What’s more, some states are almost exclusively targeted by calls with same-state area codes. Ohio and California come out on top with 72.94% and 72.71% of unwanted calls originating from Ohio and California, respectively. Closely behind is Arkansas, with 71.87%, Kentucky at 71.85%, and Minnesota, with 71.12%. 

The residents of these states should refrain from picking up calls from unknown numbers that start with a local area code. On the other hand, residents of Alaska are least likely to receive a “local” spam call with only 11.85% of reported unwanted calls originating from an Alaskan area code. Residents of Wyoming also complain the least about same-state spam calls (27.74%). These states are followed by Montana, Hawaii and Maine which, although below 50%, show a much higher percentage of local area code spam call instances. 

With local numbers most prevalent among unwanted calls, any code is a spam area code 

The data presented above very clearly show that most states receive unwanted calls from within  state lines. Or do they? Did so many spammers really move to your state to improve their success rates? We can only assume that what we’re looking at here is what’s known as neighbor spoofing. 

Neighbor spoofing happens when the caller deliberately substitutes their number with another, to make the call appear as if it was coming from a nearby area. Spammers know very well that local calls invite trust and are more likely to be answered. 

Contrary to what we think of spam calls, there are no specific area codes to avoid, or recommendations that apply on a country level. Spammers also read the news and have adapted their techniques to our habits.

The future is now: new spam recommendations to better reflect the reality of spam calls

In the absence of a universal catalog of spam area codes to avoid, any future strategy for combating spam should focus on prevention.

The extent of the spam-call problem is ultimately related to the accessibility of personal data online. Careful digital hygiene is critical if people want to eliminate spam calls altogether. Taking proactive measures at the root by removing one’s contact information from people search sites, social media platforms, and the broader internet is unequivocally the most effective approach available today. Learn more about why you may be receiving spam calls here.

Advocacy efforts for more comprehensive data protection laws will play a pivotal role in curbing spam in the future.

Methodology

Incogni’s researchers sought out and downloaded yearly Daily Data Files from the Federal Trade Commission’s Do Not Call (DNC) registry, which is a database listing the phone numbers of individuals who have requested not to be contacted by telemarketers. 

The data represents 286,250 reports submitted to the Federal Trade Commission from 16th October to 8th December, 2023. Incogni researchers combined all the information into one database. Reports without a telephone number for the advertiser, or telephone numbers reported as “111111111” or “0” were removed from the database.

Limitations

Due to the reliance on the self-reports of people who have voluntarily registered their numbers to the Do Not Call Registry, the data may not comprehensively represent all instances of unwanted calls or be generalizable to the US population as a whole.

The data used in this research is available here: Public dataset.

Sources

  1. Federal Communication Commission. “Consumer Guide. What is a Toll-Free Number and How Does it Work?” Accessed January 3, 2024. https://www.fcc.gov/sites/default/files/what_is_a_toll_free_number_and_how_does_it_work.pdf.
  2. Federal Trade Commission. “Data sets. Do Not Call Data.” Accessed December 14, 2023. https://www.ftc.gov/policy-notices/open-government/data-sets/do-not-call-data
  3. Federal Trade Commission. “National Do Not Call Registry FAQs.” Accessed November 9, 2023. Accessed January 3, 2024. https://consumer.ftc.gov/articles/national-do-not-call-registry-faqs.

Google search engine results in the US for the keyword “spam area codes.” Search performed January 3, 2024. https://www.google.com/search?q=spam+area+codes&oq=spam+area+codes.

Additional charts

Other area codes often considered spam

When we examined Google search estimates for queries such as ‘is area code X + spam,’ we found that these area codes were among the most searched:

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