In its just released report on the Muslim population worldwide, The Pew Forum claims that Muslims constitute .8 percent of the American population. A year ago, its Landscape Survey reported that Muslims made up .6 percent of the American population. But this was not what that survey of 35,000 found. In a conference call for journalists, Luis Lugo said that Muslims had come in at just .3 percent of actual respondents–a number adjusted for statistical reasons to .4 percent. Pew chose to report .6 percent because that was the conclusion of its 2007 survey of Muslim Americans. Its rationale for substituting it for the actual Landscape Survey findings seemed less than plausible to me.

The only explanation for how the present .8 percent was arrived at is the following footnote, from page 24:

There has been considerable debate over the exact number of Muslims in the United States. The 2.5 million figure is a projection for 2009 based on the Pew Research Center’s 2007 survey “Muslim Americans: Middle Class and Mostly Mainstream” (http://pewforum.org/surveys/muslim-american/) and available Census Bureau data (http://factfinder.census.gov/), adjusted for U.S. population growth. For a discussion of the larger debate, see http://pewresearch.org/pubs/532/questions-muslim-survey.

I don’t understand how .6 percent in 2007 projects to .8 percent in 2009. But based on the actual Landscape Survey findings, Pew has now doubled its estimate of the proportion of Muslims in America. By way of comparison, the 54,000-respondent 2008 Trinity ARIS found the number to be .6 percent. That’s good enough for me.