Published reports on studies in clinostats and random positioning machines frequently do not include adequate operational data on physical parameters of the culture device or cell culture conditions. This failure to report minimum physical and chemical data on how experiments are performed makes it impossible to determine specific hardware utilization or to calculate forces delivered. This makes experimental comparisons difficult and isolation of critical methodological differences between investigational results impossible. A minimum set of parameters to be reported in clinostat or random positioning machines is proposed to be known as the Bonn criteria. For random positioning machine experiments, the minimum experimental parameters to be reported should include angular velocity of rotation, highest angular acceleration, operating mode (random, centrifuge, or clinostat in rpm or freely programmable mode). For both clinostat and random positioning machines, experimental reporting should include the properties of the culture vessel, culture media and carrier beads. These should also include dimensions and rotation speed of vessel, chemical consistency including density and viscosity of media, size, density, and porosity of beads, size, density, and porosity of cells, whether cells are motile or non-motile, density of beads with cells attached, as well as time of rotation, nature of controls, operating temperature, and gas content.