Consumer complaints and the growth of national “do not call” lists have made it more challenging for telemarketers to use “robocalls,” those automated phone calls used for surveys and mass marketing. Now a new method for research and marketing is giving new life to the telemarketing industry.

Many Americans find spam phone calls from outbound dialing, the most common form of telemarketing, annoying and disruptive, according to CNBC. Telemarketers are gradually dropping this approach, given the challenges of compiling lists of new phone numbers and of people simply not answering their phones.

Instead, a new model is gaining ground within the industry. Instead of calling consumers, telemarketers are now buying phone numbers and waiting to speak to those who accidentally call. Telemarketers look at widely used numbers, such as customer service numbers for large banks or other institutions, and then they purchase a number that is close but typically one digit off.

For example, if a credit card customer service number starts with “804,” a telemarketing firm could purchase that number starting with “800.” Since many consumers will misdial, as “800” is a more common start for many commercial lines, the wrong number may be called thousands of times a day.

A telemarketing company that owns even a small cache of such wrong numbers may receive as many as 2.5 million calls a day. According to the market research firm Reconnect Research, 14.5 percent of people who dial a wrong number will stay on the line long enough to take a three minute survey.

Reconnect says that there are 5 to 10 billion such misdialed or otherwise disconnected calls in the U.S. each month. The firm manages about 100 million such calls a month.

Reconnect says that people who initiate a call stay on the line for surveys and other marketing because as the caller, they expected to speak to someone – unlike a call recipient who feels bothered by the unwanted marketing call. The company believes their method delivers more accurate polling and market research, as the cross-section of those who dial wrong numbers is more representative than for those who still answer a land line phone.