The design of passenger terminals is a complicated process. One of the inputs into this process is an approximation of space required per passenger at each of the various processing phases such as check-in, baggage claim, security and retail. The allocation of space to each of these areas is guided by a set of metrics known as “Level of Service”.
The terms “level of service” and “quality of service” have been used almost interchangeably in the aviation literature. Most importantly, neither phrase uses the conventional meaning of the term “service”, i.e. an act or helpful activity. In this context, service refers to the range of acceptable area per passenger (in square meters), as defined by a six point scale (ranging from A-best, to F-worst).
The inclusion of the word “service” in the Level of Service standards reveals a hidden assumption, namely, that more area per passenger equates to better service. Thus, the metrics contain an implicit (flawed) relationship between space and service: the levels of service (A to F) are associated with both space (per passenger) and a qualitative description (Excellent, High, Good, Adequate, Inadequate, Unacceptable). Although there is unarguably a minimum amount of space required for humans to function, there is no evidence that the more space allowed per passenger, the better the terminal design, or the better the “service” experienced by the passenger.
This inherent and paradoxical relationship between service quality and space injects an air of confusion that adherence to the Level of Service standards will result in the provision of superior service to passengers.
Sources: An excerpt of the LOS Standards for check-in areas can be found in Challenges in Passenger Terminal Design. IATA Airport Development Reference Manual contains details of the LOS Standards. A more recent evaluation of the LOS Standards by ACRP.