Productivity refers to the efficiency with which output is produced using the available inputs (labor, capital, land, intermediate inputs such as materials and energy). Productivity can be defined in terms of a single factor input, such as labor productivity, or in terms of all the factor inputs, which is multifactor productivity (MFP). BTS research estimates and analyzes MFP for the various subsectors (transportation modes) of the transportation sector. BTS also analyzes labor productivity of the various transportation modes.