Abstract
<p>Social surveys commonly measure single religious belonging (SRB). Critics suggest SRB fails to group religionists meaningfully outside the West, where hybrid religiosity is normal. This study challenges that premise. Using the 2023 Taiwan Social Change Survey, I find SRB predicts 25 of 27 religiosity outcomes. Its power may vary. SRB separates Christians from everyone else almost perfectly, and Yiguandao just as well. Protestants and Chinese traditions rarely cross the Jesus worshipping boundary. And while Buddhists, Daoists and folk religionists share one pantheon, they rank it differently and follow different rules on diet, pilgrimage and initiation, so plural worship may mark syncretism rather than plural belonging. I then test whether granularity of SRB matters. Asking more denomination and taking refuge questions moves Buddhists and folk religionists between categories, but does not change the predicted pattern. Where SRB is thin, the remedy is a finer question about practice, not more boxes.</p>