Quantitative Share Index or Quality of Service Index(qst Definition Quantitative Share Index or Quality of Service Index(qst There is a QSI for each itinerary i in each market m for each airline a, denoted esli(m) The sum of esT i(m/over all itineraries i in a market m over all airlines a is equal to 1, for all markets m 2/212021 Barnhart 1.206J/16.77J/ESD. 15J2/21/2021 Barnhart 1.206J/16.77J/ESD.215J 10 Quantitative Share Index or Quality of Service Index (QSI): Definition • Quantitative Share Index or Quality of Service Index (QSI) – There is a QSI for each itinerary i in each market m for each airline a, denoted QSIi(m) a – The sum of QSIi(m) a over all itineraries i in a market m over all airlines a is equal to 1, for all markets m