  Opinion polls remain among the most efficient and widespread methods to
capture psycho-social data at large scales. However, there are limitations on
the logistics and structure of opinion polls that restrict the amount and type
of information that can be collected. As a consequence, data from opinion polls
are often reported in simple percentages and analyzed non-parametrically. In
this paper, response data on just four questions from a national opinion poll
were used to demonstrate that a parametric scale can be constructed using item
response modeling approaches. Developing a parametric scale yields
interval-level measures which are more useful than the strictly ordinal-level
measures obtained from Likert-type scales common in opinion polls. The metric
that was developed in this paper, a measure of religious morality, can be
processed and used in a wider range of statistical analyses compared to
conventional approaches of simply reporting percentages at item-level. Finally,
this paper reports the item parameters so that researchers can adopt these
items to future instruments and place their own results on the same scale,
thereby allowing responses from future samples to be compared to the results
from the representative data in this paper.
