Total factor productivity (TFP) is often considered the primary contributor to GDP growth rate. Other contributing factors include labor inputs, human capital, and physical capital. Total factor productivity measures residual growth in total output of a firm, industry or national economy that cannot be explained by the accumulation of traditional inputs such as labor and capital. Since this cannot be measured directly the process of calculating derives TFP as the residual which accounts for effects on total output not caused by inputs.
