Statcast Number 12 Transcript

DATE: March 11, 2009

PUBLICATION: “Wireless Substitution: State-level Estimates from the National Health Interview Survey, January-December 2007”

SPOKESPERSON: Stephen Blumberg, a health statistician with the National Center for Health Statistics, discusses the results of a new report on wireless-only phone use by state.

Announcer: We’re joined by Stephen Blumberg, a health statistician with the National Center for Health Statistics. Stephen is the lead author of a new report on wireless-only phone use by state. Stephen, what states are leading the “wireless-only” movement in this country?

Stephen: The report that we just released, looks at data from 2007, and in 2007, Oklahoma, Utah, and Nebraska had the highest prevalence of wireless only households.

Announcer: So can you tell me why NCHS is studying wireless phone use? I mean, it doesn’t seem like a health-related item.

Stephen: NCHS, as well as CDC and other organizations conduct a number of telephone surveys in order to understand in our case the health of the nation. Those telephone surveys typically do not include cellular phone numbers when contacting individuals. As the prevalence of the wireless-only population grows, more and more people aren’t eligible for those surveys–that can lead to bias.

Announcer: So back to the numbers–what states have the smallest percentage of wireless-only phone use?

Stephen: Well, if we look at who essentially has the fewest number, or fewest proportion of households, that are wireless only, we’re looking at states such as Vermont, Connecticut, Delaware, and South Dakota.

Announcer: Among the different regions, were there some regions that had higher cell phone use than others?

Stephen: What we found interesting was that even within regions of the country we saw some great variation between the states. So, for instance, in the Midwest, we found that the state with the highest prevalence of wireless-only households actually shares a border with the state with the lowest prevalence of wireless-only households. That is, Nebraska was the highest and South Dakota was the lowest in the Midwest.

Announcer: I guess the question is, why does Oklahoma and some of the other states have such a high percentage of wireless-only phones?

Stephen: That’s a good question. One of the interesting things that we looked at in this report were the demographics that best predicted wireless-only prevalence. Now we know from our previous reports that renters are about 4 times as likely to be wireless only as people who own their home. We know that young adults 18 to 30 are more likely to be wireless only. We know that adults who are living in poverty or with low incomes are more likely to be wireless only. When we look at the state level prevalence estimates, we see very similar relationships. So, for example, Oklahoma, Utah, Nebraska, Iowa—these states have a relatively high prevalence of households that contain only adults 18 to 30 years of age–so essentially households headed by young adults. We see in Utah, Nebraska, and Iowa a large percentage of households that are both rented and headed by someone 18 to 30 years of age. So for these states, we would expect–and we saw a–relatively high prevalence of wireless only households.

Announcer: How do the rates in the states compare to those you see at the national level?

Stephen: Well, remember these data are from 2007, so in 2007, approximately 15% of households were wireless only. Now that rate has been growing; it tends to grow at about 3 percentage points a year. Now in 2009, we would expect that all of those prevalence estimates have increased by some degree. Now, we don’t know if every state is growing at the same rate or not.

Announcer: In the course of doing this study, were you able to see any trends as far as growth of cell phone usage in the states themselves?

Stephen: We don’t have trends by state. NCHS has been tracking the proportion of wireless-only households since 2003. This however is the first time that we’ve looked at state-level estimates. So we won’t be able to address trends at the state level until our next report. And I would hope that we can update these numbers later this year.

Announcer: Our thanks to Stephen Blumberg for joining us on this edition of “StatCast.” “StatCast” is produced by the Public Affairs Office at the National Center for Health Statistics.