Series correction is simpler than parallel correction. However, series correction devices often suffer from severe gain attenuation, so the use of series correction often requires the introduction of additional amplifiers to increase gain and provide isolation. For parallel correction, the signal is always transmitted from a higher power point to a lower power point, without the need to introduce additional amplifiers, and the number of components required is often less than for series correction. Which type of correction is used in control system design often depends on factors such as correction requirements, signal properties, power at each point in the system, optional components, and economy.