The Pew Research Center released its latest numbers on home broadband adoption this week, reporting that seven in ten American adults now have a broadband connection at home. The report also found that one in ten Americans own a smartphone but lack home broadband.

Since the report was published, we’ve received a few questions about how we measure and report broadband adoption in America.

How do you define “broadband”?

Our broadband question has historically tried to distinguish between dial-up users and those with higher connection speeds. It gives a general measure of “broadband” users in the United States, and tracks pretty well with government data on broadband adoption.

Because our research is based on nationally-representative phone surveys, we rely on self-reported data—in other words, we just ask. Specifically, we ask adults who say they use the internet at home: “At home, do you connect to the Internet through a dial-up telephone line, or do you have some other type of connection, such as a DSL-enabled phone line, a cable TV modem, a wireless connection, or a fiber optic connection such as FIOS?”

We have asked about home broadband since 2000, and have asked a version of this question since 2003. This allows us to see changes in how people connect to the internet during the last decade, as shown in the accompanying chart.

As of May 2013, 70% of American adults ages 18 and older say they have some type of broadband connection at home, and 3% say they have dial-up. (Note: We suspect that many “wireless” respondents in our home broadband number include people with wired DSL or cable connections via wireless routers, as opposed to strictly “wireless” satellite or Aircard users.)

What type of connection speeds do you measure?

The short answer is: We don’t. It is often very difficult for people to answer detailed questions about their internet connection type and speed. In 2010, for instance, we asked about “premium” vs “basic” service, but about 13% of broadband users weren’t sure of what type they had. When we’ve asked specifically about broadband users’ connection speed, the vast majority (about 90%) of respondents said they did not know.

One source of detailed data on this topic is the National Broadband Map, an interactive from the National Telecommunications and Information Administration (NTIA). It has lots of information about types of connection, broadband speeds (including advertised speeds, typical speeds, and the results of speedtests), and general availability by state, county, metropolitan area, and more.

Do you count Americans who rely on smartphones for home internet access as “broadband users”?

No. There is no widespread consensus as to whether 3G or 4G smartphones qualify as “broadband” speed, and many would question whether they offer the same utility to users as a dedicated home internet connection—activities such as updating a resume, filing taxes, or viewing educational content are certainly more challenging on a smartphone operating over a cell phone network, than on a broadband-connected home computer. For these reasons, smartphones are qualitatively distinct enough that we do not include them in our standard definition of what constitutes a “broadband user.”

In other words, when we write that 70% of adults have home broadband, that does NOT include the 10% of adults who do not have broadband but do own a smartphone.

Kathryn Zickuhr  is a former Research Associate at the Pew Research Center’s Internet & American Life Project.