The quotient of two rates where the quantities are of the same kind in the same system for different components: \[\frac{\text{d}Q_{1}/\text{d}t}{\text{d}Q_{2}/\text{d}t}\] For finite time intervals, mean rate of change ratio is: \[\frac{\Delta Q_{1}/\Delta t}{\Delta Q_{2}/\Delta t}=\frac{\Delta Q_{1}}{\Delta Q_{2}}\ \Delta t\] Rate of change ratio has the dimension one. The denominator is often called the reference quantity. Examples are: mass rate ratio, (dm1/dt)/(dm2/dt); amount of substance rate ratio, (dn1/dt)/(dn2/dt).