The seven groups
Traditional, actively involved in congregation.
Less active at church, socially and politically conservative, anti-immigrant
Traditional plus belief in psychics, reincarnation, and spiritual energy
Religion important personally but not necessary to be moral, not engaged in traditional practices
Believe in heaven, hell, and New Age belief, but do not engage in traditional practices
Believe organized religious more bad than good, politically liberal and Democratic
Virtually no religious beliefs, reject New Age beliefs
Because the seven groups are constructed based on religious behaviors and beliefs, they will cut across the denominational identities often used to classify individuals. For example, 13% of the Sunday Stalwarts are Catholic, but 25% of the Relaxed Religious are Catholic, as are 9% of the Religious Resisters. Also, the Sunday Stalwart group includes individuals from non-Christian faiths (even though the do not technically worship on Sunday).
A primary merit of this seven-group classification is that it highlights some of the diversity in the American religious marketplace. The challenge, of course, is to find the right number of groups. To many and the classifications become meaningless, but too few and the classifications are also meaningless. For this report, Pew used a statistical procedure called cluster analysis to let the data reveal what appear to be statistically coherent subgroupings in the data. Doing this does involve making assumptions, such as what are the crucial data to include in the analysis. Here, Pew included data from 16 particular survey questions about religious practices and broad beliefs.
Of course, this procedure ignores other forms of diversity, such as more particular theological beliefs, that are not captured in those 16 questions. But this is the nature of social scientific inquiry: some data are privileged over others, wisdom and care should be used in deciding on what is privileged; and honesty about the pros and cons and strengths and weaknesses of the analysis and results should be maintained.