This manual was developed to assist interested parties in using the Global Warming’s Six
Americas audience segmentation typology. The segmentation typology is fully described in
Maibach, Leiserowitz, Roser-Renouf, & Mertz (2011).
In brief, the segmentation analysis was performed by subjecting 36 variables to Latent Class
Analysis (Magidson & Vermunt, 2002a, 2002b); the variables were drawn from four categories:
global warming beliefs, issue involvement, climate-relevant behaviors, and preferred societal
responses. The resulting six audience segments – which form a continuum – were named the
Alarmed, Concerned, Cautious, Disengaged, Doubtful and Dismissive. A description of these
audience segments can be found in the Maibach et al. paper, and in a variety of reports located
in the resources sections of George Mason University’s Center for Climate Change
Communication website (http://climatechange.gmu.edu) and the Yale Project on Climate
Change Communication website (http://environment.yale.edu/climate).
Also described in the Maibach et al. article are two survey tools – a 36-item instrument and a
15-item instrument – that we developed for our own use, and for use by other researchers to
identify the Six Americas in new, independent data sets. These tools were created using linear
discriminant functions (Hair, Anderson, Tatham & Black, 1992; Tabachnik & Fidell, 1989) to
identify Six America segment status.
The discriminant analysis using the 36-item instrument correctly classifies 90.6% of the sample
(as compared to the original Latent Class Analysis results); accuracy varies by segment, ranging
from 79% to 99%. The 15-item instrument correctly classifies 84% of the sample, ranging by
segment from 60% to 97%.
Both of these instruments – along with codebooks, and SAS and SPSS scripts that run the
discriminant functions – are provided in this manual. Additional SAS files that include the
discriminant functions are needed in order to run the SAS scripts, and should be downloaded
along with this manual.