Strict churches are strong because they reduce free riding by screening out members who lack commitment and encouraging participation among those who remain. Rational choice theory explains the success of strict religious groups without assuming irrationality or misinformation. Strictness increases commitment, participation, and perceived benefits, making such groups more attractive. However, there is an optimal level of strictness beyond which it becomes counterproductive. The article argues that Kelley's thesis is correct, and that strictness enhances group strength by mitigating free-rider problems. It also highlights the importance of adapting strict demands to social change. The article discusses how strictness can be measured by the cost of non-group activities, such as socializing with members of other churches or pursuing secular pastimes. Strict churches often require members to sacrifice time, money, and social opportunities, which can increase their perceived value. However, these sacrifices may not always be beneficial, as they can lead to social isolation and reduced participation. The article also notes that strictness can lead to increased group cohesion and commitment, but only up to a point. The article provides evidence that strictness correlates with higher rates of church attendance and contributions, closer ties to the group, and reduced involvement in competing activities. It also shows that strictness is more prevalent in conservative denominations than in liberal ones. The article argues that strictness is not inherently pathological but can be a rational strategy for religious groups to enhance their appeal and maintain membership. The article also discusses the social correlates of sectarianism, noting that individuals with limited secular opportunities are more likely to join strict groups. It also highlights the importance of balancing strictness with adaptability to social change, as overly strict groups may fail to attract members. The article concludes that strictness is a rational strategy for religious groups to enhance their appeal and maintain membership, but it must be balanced with adaptability to social change.Strict churches are strong because they reduce free riding by screening out members who lack commitment and encouraging participation among those who remain. Rational choice theory explains the success of strict religious groups without assuming irrationality or misinformation. Strictness increases commitment, participation, and perceived benefits, making such groups more attractive. However, there is an optimal level of strictness beyond which it becomes counterproductive. The article argues that Kelley's thesis is correct, and that strictness enhances group strength by mitigating free-rider problems. It also highlights the importance of adapting strict demands to social change. The article discusses how strictness can be measured by the cost of non-group activities, such as socializing with members of other churches or pursuing secular pastimes. Strict churches often require members to sacrifice time, money, and social opportunities, which can increase their perceived value. However, these sacrifices may not always be beneficial, as they can lead to social isolation and reduced participation. The article also notes that strictness can lead to increased group cohesion and commitment, but only up to a point. The article provides evidence that strictness correlates with higher rates of church attendance and contributions, closer ties to the group, and reduced involvement in competing activities. It also shows that strictness is more prevalent in conservative denominations than in liberal ones. The article argues that strictness is not inherently pathological but can be a rational strategy for religious groups to enhance their appeal and maintain membership. The article also discusses the social correlates of sectarianism, noting that individuals with limited secular opportunities are more likely to join strict groups. It also highlights the importance of balancing strictness with adaptability to social change, as overly strict groups may fail to attract members. The article concludes that strictness is a rational strategy for religious groups to enhance their appeal and maintain membership, but it must be balanced with adaptability to social change.