Amish demography

Reviving the Demographic Study of the Amish

“…In one Amish sub-faction, the average relatedness of married couples is a little closer than second cousins, which is actually more distant than had all members been randomly paired (Hurd 1985); in a large Pennsylvania settlement, the inbreeding level nearly equates to second cousins (Dorsten, Hotchkiss, and King 1999;Khoury, et al 1987a). Further, because Amish rarely marry across sub-affiliation lines (Hurd 1997) or across settlements, and because they usually stay in the community in which they were born (Cross and McKusick 1970;Donnermeyer and Cooksey 2004), inbreeding is intensified, each major settlement representing a genetic sub-isolate (Cross 1976). High levels of relatedness are positively associated with farming as an occupation, younger age at marriage, higher number of siblings, and having a common last name (Khoury, Cohen, et al 1987a).…”

“…Amish population pyramids diverge sharply from non-Amish neighbors (Enninger & Wandt 1982;Hewner 1997;Hostetler 1980), consisting of a full bottom and narrow top, with studies reporting given settlements at a majority under 20 (Cross & McKusick 1970), 46% younger than 15 (Greksa 2002), and a 100:110 to 113.5 baptized to unbaptized (pre-adult) ratio Smith 1960), among others (Hewner 1998). Consequently, population doubling is rapid, occurring every 22.5 to 23 years (Cross and McKusick 1970;Donnermeyer and Cooksey 2004;Greksa 2002) or decennially increasing by 30% to 47% across the century . The percent elderly among the Amish remains consistent at around 2%-3% (Hewner 1997).…”

“…Completed family live births vary by settlement and twentieth century cohort, but are all high, including 6.33 (Cross and McKusick 1970) , 6.8 (Ericksen, et al 1979), 7.1 (Kraybill 2001), 7.6 (Dorsten 1994), 7.7 (Greksa 2002, and 7.8 (Acheson 1994). Through most of the past century, fertility increased slightly (Cross and McKusick 1970;Ericksen, et al 1979;Markle and Pasco 1977), even experiencing an additional increase during the baby boom (Bailey and Collins 2011), though one large, high birth settlement declined by one child by 1967 (Greksa 2002) and another large settlement experienced a slight decrease among late century cohorts (Dorsten 1999). …”

“…In the twentieth century Amish marriages took place around the national average, a little over 21 years of age (Acheson 1994;Cross & McKusick 1970;Donnermeyer and Cooksey 2004). At midcentury, males tended to marry slightly younger and females slightly older than national averages (Smith 1960), with overall marriage age and the number unmarried by 30 decreasing slightly across the century (Donnermeyer and Cooksey 2004).…”

“…Amish have been useful for demographic and genetic studies because they are highly independent of larger society, are endogamous and therefore have a closed gene pool, keep meticulous genealogies, are relatively homogenous in socio-economic indicators, have very low rates of infidelity and divorce, possess relative socio-economic consistency across the population, create permanent conjugal institutions in which nearly all children are born, and have comparatively large families (Cross 1976;Cross & McKusick 1970;McKusick, et al 1964). Amish population growth results from high birth rates, low death rates, and high retention rates (Donnermeyer & Cooksey 2004;Smith 1961), albeit not a high non-Amish conversion rate.…”