Cost-effective Design of Growth Studies with Aggregation and Tracking

Abstract

Studies of the development and growth of organisms are often conducted in laboratories where organisms maintained in tanks are examined repeatedly over time. Collection and recording of cross-sectional aggregate count data on stage occupancy is both less expensive and administratively more convenient than tracking the stages of each organism over time. In such settings tank to tank variation must also be taken into account as growth rates may be more similar among organisms within the same tank than for those in different tanks. We consider the cost effect design of a prospective developmental study of organisms based on a marginal Markov model which deals with between tank variation and within tank dependence. We develop a flexible design in which some tanks provide repeated cross-sectional aggregate data, and other tanks provide serial responses through tracking individuals. We assess the relative efficiency of aggregate and individual-level longitudinal data. The optimal cost-effective design is shown to depend on whether primary interest lies in transition intensities or associated cluster-level covariate effects. Citation: Jiang S, Cook RJ (2018) Cost-effective Design of Growth Studies with Aggregation and Tracking. J Biom Biostat 9: 406. doi: 10.4172/21556180.1000406