Coastal ports efficiency evaluation and analysis when considering undesirable output

With the rapid development of China's economy, port pollution problems become serious in China. Port efficiency evaluations which take undesirable environmental outputs into consideration tend particularly important. Based on this observation, in this paper, we take pollution emissions as undesirable outputs and employ generalised directional distance function (GDDF) to evaluate the technical efficiency (TE) and comprehensive efficiency (CE) for the 21 coastal ports in China. Results show that: 1) for each of the ports, its CE value is higher than its TE value after considering undesirable output in efficiency evaluation during 2008-2012; 2) TE and CE values of the five port groups differ significantly, and 'strong north and weak south' phenomenon appears; 3) efficiency gaps among ports are obvious; 4) in order to achieve higher CE values, the southeast coastal port group, the southwest coastal port group and the pearl river delta port group need to reduce investment greatly.