Efficiencies of Agricultural Credit Associations of the US Farm Credit System are measured quarterly from 2005 through 2020. A slacks-based measure based on the directional distance function is used with non-performing loans included as an undesirable output. This permitted efficiency scores to be measured by type of defined input or output. Generally, most Associations were highly efficient, but there was deterioration in mean efficiency over the years 2008–2018, a period of financial difficulties in the US agriculture. Efficiencies of Associations that merged or consolidated were tracked before and after these activities. Mergers and consolidations often led to increased efficiencies.

When a free-ranging walking machine carries its own fuel and power source as well as a payload, it is important to maintain high mechanical efficiency. If the masses of the legs are negligible then, in a straight and level walk, the only power to be generated would be that needed to overcome ground and wind resistance and internal frictions. The paper shows this to be the case when one-input straight-line generating mechanisms are used. However, when two-input mechanisms are used the actuators can work against each other resulting in finite, sometimes large, power requirements. The paper determines the effects of limb lengths and ground clearance on step length and quantifies the power requirements of serial-operated and parallel-operated legs. It shows that parallel-operation offers greater efficiency.