DESCRIPTION OF "MARKET DATA" FILES CREATED BY SEVERIN BORENSTEIN

The "Market Data" files replace the "Market Share" data files that I previously released. Unlike the Market Share files, the Market Data files include interline one-way tickets. These were rare in the 1990s when I created the Market Share files, but have become quite common with regional airlines code-sharing with majors. Also, the Market Data include all carriers, not just the 30 largest, and include all routes. As a result, these are larger than the Market Share datasets. The structure is somewhat different as well.

The Market Data files are available as Stata datasets. They are created from the domestic airline ticket data from the DOT's Databank 1A/1B (DB1A), a 10% sample of all tickets collected by US carriers.

-- Tickets with an international segment are excluded.

-- Tickets with a First-class or Business-Class segment are excluded.

-- Tickets must be one-way or round-trip; open-jaw, circle trips,

etc are excluded.

-- A ticket must have no more than 2 coupons for a one-way trip, no more

than 4 coupons (and no more than 2 coupons each way) for a rountd-trip

ticket.

-- Tickets with fare less than $20 or fares above $9998 excluded.

-- Tickets with fares more than 5 times USDOT's Standard Industry Fare Level for that trip distance in that quarter are excluded.

-- Records are for one-way trips, so round-trip tickets are split into two one-way observations

-- The Market Data dataset reports operating carriers, but drops information on ticketing carriers

The Stata dataset has one record per route/carrier-set/dir-cop where

-- route is a pair of airports without regard to direction (ordered alphabetically)

-- carrier-set is one carrier and a blank if the trip is one-coupon. If the trip is two-coupon, carrier-set is the pair of airlines that provided the service on the two legs (possibly the same carrier) with carrier codes listed in alphabetical order. Information about the order of flights is not retained.

-- dir-cop is a distinction between one-coupon and two-coupon tickets. On two-coupon tickets, the location of the change-of-plane is not retained, though the average total routing distance for all c-o-p tickets that have been collapsed into a single record is reported.

The dataset includes the following variables

yr -- year

qtr -- quarter

ap1 -- 3-letter alpha code of the first airport (by alphabetical ordering)

ap2 -- 3-letter alpha code of the second airpor (by alphabetical ordering) - blank if one-coupon ticket

cr1 -- 2-letter alpha code of the first operating carrier (by alphabetical ordering)

cr2 -- 2-letter alpha code of the second operating carrier (by alphabetical ordering) - blank if one-coupon ticket

pax -- number of passengers reported in record

nsdst -- non-stop distance from airport ap1 to airport ap2

avdst -- average total routing distance of passengers in this record - equal to nsdst if one-coupon ticket

avprc -- average one-way equivalent price paid by passengers reported in this record

cop -- 0 if one-coupon ticket, 1 if two-coupon ticket

The Market Data dataset is available for 1979 to 2009, though there are data reliability issues for the first few years, and particularly for 1980q4 when EA and DL significantly under-reported.