The analysis in this report is based on a survey conducted June 29-August 8, 2012 among a sample of 9,513 adults, 18 years of age or older. The survey was conducted by GfK Knowledge Networks (KN) among a random sample of households in their nationally representative online research panel. KN panel members are recruited through probability sampling methods and include both those with internet access and those without (KN provides internet access for those who do not have it and, if needed, a device to access the internet when they join the panel). A combination of random digit dialing (RDD) and address-based sampling (ABS) methodologies have been used to recruit panel members (in 2009 KN switched their sampling methodology for recruiting panel members from RDD to ABS). The panel includes households with landlines and cell phones, including those only with cell phones, and those without a phone. Both the RDD and ABS samples were provided by Marketing Systems Groups (MSG). KN continually recruits new panel members throughout the year to offset panel attrition as people leave the panel. The survey was conducted in English.
Respondents were selected randomly from eligible adult household members of the panel. A total of 9,513 adults responded to the initial screener questions to determine whether they owned a smartphone or tablet computer; the 4,875 who did not own either device were terminated and did not receive any additional questions. To reach target sample sizes, sample selection procedures were used to terminate certain respondents. Of the 2,013 adults who own and use a tablet computer and the 3,947 adults who own a smartphone, 45% of smartphone owners (including those who also own a tablet) were randomly selected to continue with the survey (while the other 55% were terminated) after answering questions about how often they did certain activities on their tablet (Q.14) and/or smartphone (Q.54), including get news on their devices; the order of the tablet and smartphone series was randomized for those with both devices. All of those who got news on their mobile device weekly or more continued with the remainder of the interview while 33% of those who did not consume news on their device weekly continued (and 67% were terminated). This resulted in a sample of 810 tablet news users and 1,075 smartphone news users who received the full survey, including the detailed questions about news consumption on their mobile devices and other platforms. The survey was fielded in two parts. The first phase was conducted from June 28-July 17,, 2012 with 2,051 adults interviewed. After analysis of the preliminary data and a few telephone follow-up interviews were conducted, a few small changes were made to the questionnaire (and are noted in the topline), and the second phase was conducted August 1-8, 2012 with 7,462 adults interviewed. All sampled members received an initial email to notify them of the survey and provide a link to the survey questionnaire. Additional follow-up reminders were sent to those who had not yet responded as needed.
The final sample of 9,513 adults was weighted using an iterative technique that matches gender, age, race/ethnicity, education, region to parameters from the June 2012 Census Bureau’s Current Population Survey (CPS). In addition, the sample is weighted to match household income to a parameter from the March 2011 CPS survey and to match current patterns of internet access from the October 2010 CPS survey. This weight is multiplied by an initial sampling or base weight that corrects for differences in the probability of selection of various segments of KN’s sample and by a panel weight that adjusts for any biases due to nonresponse and noncoverage at the panel recruitment stage (using all of the parameters described above as well as home ownership status and metropolitan area from the June 2012 CPS). Details about the KN panel-level weights can be found at http://www.knowledgenetworks.com/knpanel/KNPanel-Design-Summary.html.
Because of the differential selection procedures employed in the survey, an additional weighting step was taken to correct for any potential bias introduced by these selection procedures (even though random selection procedures were employed). This step weighted the sample of 1,928 mobile device owners selected for the complete survey to match the characteristics of the full sample of 4,638 device owners screened. The sample was weighted using an iterative technique that matches gender, age, race/ethnicity, education, region, metropolitan area, household income, internet access and news consumption among tablet-only owners, smartphone-only owners and those that own both devices to targets derived from the weighted sample of all device owners screened.
Sampling errors and statistical tests of significance take into account the effect of weighting at each of these stages. The margin of sampling error at the 95% confidence level is plus or minus 3.4 percentage points for results based on tablet users (n=2,013) and 5.4 percentage points for tablet news users (n=810). The margin of sampling error is 2.4 percentage points for smartphone owners (n=3,947) and 4.7 for smartphone news users (n=1,075). Sample sizes and sampling errors for other subgroups are available upon request.
In addition to sampling error, one should bear in mind that question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of opinion polls.
