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Changes to Punctuality Data in 2015

4 May 2015
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2015 sees the biggest change in our punctuality data since the site was founded in 2003, with the addition of 14 airports to the current list of 10, each of which now reports monthly punctuality data, compiled and published by the CAA.

The new list of 24 UK reporting airports for punctuality from 1 January 2015, which will effectively provide almost complete national coverage, is as follows.

 UK Reporting Airports (from Jan 2015 data)
UK Reporting Airports Map
AirportIATA CodeAnnual Passengers (2014)Airline Flights (2014)
Belfast CityBHD2,555,14536,052
Belfast InternationalBFS4,033,95434,795
Doncaster SheffieldDSA724,8855,118
Durham Tees ValleyMME142,3794,048
East MidlandsEMA4,510,54457,197
Leeds BradfordLBA3,274,47429,873
London CityLCY3,647,82470,133
London GatwickLGW38,103,667254,540
London HeathrowLHR73,405,330470,708
London LutonLTN10,484,93875,616
London StanstedSTN19,941,593143,101
14 New Airports+ 35,334,853+ 453,094

Full details of the changes are available at our Data Analysis page.
Annual Passengers (2014): Terminal and Transit Passengers, UK CAA Data
Airline Flights (2014): Air Transport Takeoffs and Landings, UK CAA Data

As the table shows, inclusion of these new reporting airports will mean an additional 450,000 flights carrying over 35 million passengers per year will now be analysed.


There is an increasing duplication issue in the statistics with almost all UK airports now reporting punctuality data, in the situation where domestic flights operate between two UK reporting airports.

This is due to the fact that we analyse both departure and arrival punctuality at each UK reporting airport. A flight operated between two UK reporting airports will therefore appear twice in the data, analysed once on departure and once again on arrival.

This would create an unfair 'weighting' on the punctuality of some domestic flights over international flights for each airline.

To resolve this issue, wherever a flight operates between two of the 24 UK reporting airports we will 'weight' the data with a multiplier of 0.5 for each departure and arrival, so that the entire operation of each flight is only counted as a single flight by the airline, not as two flights.

The resultant punctuality of each flight in this case will effectively be an average of it's departure and arrival punctuality.

The duplication weighting is not applied for data in the following site sections:

 - Airport Punctuality Pages
     only departures and arrivals at that specific airport are analysed
 - Key Routes Pages
     only departures and arrivals at the London Airport(s) are analysed
 - Route analysis tables on Scheduled and Low Cost Airline pages
     only departures and arrivals at a specific airport are analysed in each table
 - Charter Punctuality Pages
     the charter flights we analyse usually do not operate between UK reporting airports

The duplication weighting is applied for data in the following site sections:

 - Monthly OTP levels
     our 'Latest OTP' section analyses departures and arrivals at all UK reporting airports
 - The Scheduled Airline League Table
     which analyses departures and arrivals at all UK reporting airports
 - The Low Cost Airline League Table
     which analyses departures and arrivals at all UK reporting airports
 - The Total Row for Detailed Airline Punctuality Tables
     which analyse departures and arrivals at all UK reporting airports

Where duplication has been accounted for by weighting the data, a note will clearly show this. Further information about duplication will be published on our Data Analysis page soon.
For more information please contact us.

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