To some extent it's statistics. Send enough messages and the odds are one will eventually get though.
> providing a standardized and objective measure of the technology's capabilities
Not really. The environment is still variable. A short message could have bounced off some random short duration reflector somewhere (aeroplane, meteor, lightning, ...) or have been refracted by some short term effect. Standardised and objective is an anechoic chamber or a cabled in attenuators/channel simulator.
> providing a standardized and objective measure of the technology's capabilities
Not really. The environment is still variable. A short message could have bounced off some random short duration reflector somewhere (aeroplane, meteor, lightning, ...) or have been refracted by some short term effect. Standardised and objective is an anechoic chamber or a cabled in attenuators/channel simulator.