Generally, the performance of a sensor array tends to increase with the number of sensing elements, as each additional sensor provides additional information about the gas , albeit with diminishing marginal returns . If the number of sensors is fewer than the number of components in the gas phase, multiple distinct gas compositions produce an identical sensor array response and hence are indistinguishable by the array . Deciding the number of sensors to comprise the array likely involves a tradeoff between performance, cost, and complexity.