Compare methods

	Religious Vitality Index	Religious Attendance Measurement
Field	Sociology Of Religion	Sociology Of Religion
Family	Process / pipeline	Process / pipeline
Year of origin	1994	1993
Originator	Laurence R. Iannaccone	C. Kirk Hadaway, Penny Long Marler & Mark Chaves
Type	Index/model of religious group strength via strictness	Measurement and bias-correction for religious service attendance
Seminal source	Iannaccone, L. R. (1994). Why Strict Churches Are Strong. American Journal of Sociology, 99(5), 1180-1211.	Hadaway, C. K., Marler, P. L., & Chaves, M. (1993). What the Polls Don't Show: A Closer Look at U.S. Church Attendance. American Sociological Review, 58(6), 741-752.
Aliases	Church Strength Index, Strictness-Vitality Measure, Religious Group Strength Model, Free-Rider Vitality Index	Church Attendance Measurement, Worship Attendance Overreporting Correction, Time-Diary Attendance Measurement, Attendance Self-Report Validation
Related	3	3
Summary	The religious vitality index operationalizes Laurence Iannaccone's celebrated argument, in his 1994 American Journal of Sociology article 'Why Strict Churches Are Strong,' that demanding religious groups are often the most vital. The seeming paradox dissolves once religion is viewed as a collective good vulnerable to free-riding: if members can enjoy the fellowship, enthusiasm, and mutual support of a congregation while contributing little, average commitment erodes and the group weakens. Strictness - costly, distinctive demands such as dress codes, time obligations, and behavioral prohibitions - works as a screening device that drives out the half-hearted and raises the average commitment of those who remain. The vitality index therefore models a group's strength as a function of its strictness, its members' participation, and its capacity to retain and mobilize committed adherents.	Religious attendance measurement addresses a deceptively simple question - how often do people actually attend religious services? - and the systematic bias that plagues the obvious answer. Hadaway, Marler, and Chaves's 1993 American Sociological Review article 'What the Polls Don't Show' demonstrated that Americans substantially overreport church attendance: when they compared the roughly 40 percent weekly attendance that polls report with actual head counts in congregations, they found real attendance was far lower, around 20 percent for Protestants and 28 percent for Catholics. The method therefore centers on validating self-reports against independent benchmarks - direct counts and, in later work, time-use diaries - and on correcting survey estimates for the overreporting that arises because attendance is socially desirable and respondents answer with an identity rather than a tally.