Background Notes

Periodicity

Monthly - rolling three month release.

Scope

Overseas Travel.

Coverage

This release covers Overseas Travel into and out of the Republic of Ireland, however travel by residents of Northern Ireland into or out of the Republic of Ireland or domestic travel within the Republic of Ireland is excluded.

Data Collection

Data from the Country of Residence Survey (CRS) is used in this release.  This survey is conducted at Dublin, Cork, Shannon, Knock and Kerry airports and Rosslare, Ringaskiddy and Dublin seaports.  Residency data is collected from passengers by a Central Statistics Office (CSO) interviewer.  Surveys are also conducted on behalf of the CSO at Holyhead Port by the UK's Office of National Statistics.

Sample Design

A sample of flights and sailings is selected to facilitate proper representation of airport/seaport pairings, day, night, week day and weekend flights/sailings.

On the selected flights/sailings for the CRS, a 1 in 5 (20%) systematic sample of passengers is selected and their country of residence is recorded.

Sample results are grossed to total passenger numbers travelling for each airport or seaport pairing, as provided by the airports and ferry companies.

Where there is no survey coverage in a period for an airport/seaport pairing, results are imputed using the 'nearest neighbour' imputation methodology.

Sample Size

The sample size for the Overseas Travel release in respect of the three month period April - June 2017 was just above 114,300 passengers.

Seasonal Adjustment

Seasonally adjusted quarterly data is available.  Trip numbers are subject to a high degree of seasonality.  These seasonal fluctuations do not affect annual comparisons but they do affect monthly or quarterly comparisons.  Typically trips are at their highest during the summer months, although there are also clear peaks around Christmas and Easter.  To facilitate interpretation of underlying trends, trip numbers are adjusted to remove these seasonal trends.  Seasonal adjustment is conducted using the direct seasonal adjustment approach.  Under this approach each individual series is independently adjusted each month, e.g. aggregate series are adjusted without reference to the component series.  Seasonal adjustment models are developed for each series based on unadjusted data from January 2000 to the current period.  These models are then applied to the entire series.  Seasonal factors are updated each quarter. 

The adjustments are completed by applying the X-12-ARIMA model, developed by the U.S. Census Bureau to the unadjusted data.  This methodology estimates seasonal factors while also taking into consideration factors that impact on the quality of the seasonal adjustment such as:

• Calendar effects, e.g. the timing of Easter (see definition (5)).
• Outliers, temporary changes and level shifts in the series.

Rounding

Individual figures have been rounded independently and the sum of the component items may therefore not necessarily add to the totals shown.

Reliability of Results 

Estimation of survey results using the above sampling design introduces a statistical variability which would not be present if all passengers from every flight/sailing had been sampled.  This means that the survey results are best estimates based on the information collected for the sample.

Airport Pairings

The CSO "Airport Pairings" database contains information on every direct flight in and out of the nine Irish airports on a monthly basis.  The most recent monthly passenger figures will be added to the database two months after the end of the reference month.  For details please go to http://cso.ie/shorturl.aspx/15

Definitions

(1) Trips

The data presented in this report is in terms of trip numbers.  A trip is defined as a journey (usually including the return) from one place to another.

(2) Visitor

The definition of Visitor used in these surveys is based on that agreed with Eurostat, the European Statistical Office.  A Visitor is defined as 'any person travelling to a place other than that of his/her usual environment for less than twelve months and whose main purpose is other than the exercise of an activity remunerated from within the place visited'.  However, as the CRS does not establish the reason for an individual's trip or length of stay, those travelling for reason of remuneration or for more than one year to a country cannot be excluded.  Therefore, trips may include those travelling for paid work.  Commercial Drivers travelling on sea routes are excluded.

(3) Country of Residence

Country of Residence is defined as the country in which the person has resided during the past year.

(4) Transit/Transfer Passengers

Transit passengers are defined as those who make a stop at an airport without any particular purpose other than being en route to another destination.  These passengers generally do not disembark from their aircraft and are not covered by the Country of Residence Survey.

Transfer passengers or 'connecting passengers' are also defined as those who make a stop at an airport without any particular purpose other than being en route to another destination.  However, unlike transits, transfer passengers disembark the aircraft and pass through the airport en route to their connecting flight.  The two flights must be booked on the same ticket for it to be considered a transfer. Such passengers are included in the estimates of trips for Overseas Travel release and are treated in the same manner as same-day visits. This is in line with UNWTO (United Nations World Tourism Organisation) International Recommendations on Tourism Statistics. Transfers are surveyed for the Country of Residence Survey.

 

Overseas Trips to Ireland and Transfer Trips
Year	Overseas trips to Ireland 1	Number of transfer trips through Dublin Airport 2
2010	6,037,100	162,100
2011	6,505,200	165,000
2012	6,517,200	201,200
2013	6,985,900	274,100
2014	7,604,400	374,600
2015	8,643,100	474,400
2016	9,584,400	583,400
1 Source: Overseas Travel Release, CSO
2 Source: Dublin Airport Authority (DAA)

 

A transfer trip is a completed journey – for example a passenger who travels from London Gatwick to Dublin Airport and then on to New York (on the one ticket) is counted as two transfer passengers and one transfer trip. 

In 2016, the number of overseas trips to Ireland increased by 10.9% when compared with 2015. Excluding transfer trips, the annual increase in overseas trips to Ireland would have been 10.2%.

 

(5) Timing of Easter

Easter falls each year on a Sunday between March 22^nd and April 25^th, inclusively.  In 2017 Easter Sunday fell on April 16^th, while in 2016 it fell on March 27^th.  Trip numbers each year are greatly influenced by when Easter falls.

Dates for Easter Sunday

2017 – 16^th April
2016 – 27^th March
2015 – 5^th April
2014 – 20^th April
2013 – 31^st March
2012 - 8^th April

Other Europe Tables 1-4, 6 and 8 Includes the following countries:
Aland Islands	Gibraltar	Netherlands
Albania	Greece	Norway
Andorra	Guernsey	Poland
Austria	Hungary	Portugal
Belarus	Iceland	Romania
Belgium	Isle of Man	Russian Federation
Bosnia and Herzegovina	Italy	San Marino
Bulgaria	Jersey	Serbia
Croatia	Latvia	Slovakia
Cyprus	Liechtenstein	Slovenia
Czech Republic	Lithuania	Spain
Denmark	Luxembourg	Sweden
Estonia	Macedonia, Former Yugoslav Republic of	Switzerland
Faroe Islands	Malta	Turkey
Finland	Moldova, Republic of	Ukraine
France	Monaco	Vatican City
Germany	Montenegro

 

North America Tables 1-4, 6 and 8 Includes the following countries:
Canada
United States

 

Other Areas Tables 1-4, 6 and 8 Includes the following countries:
Africa (see below for breakdown of countries)
Australia, New Zealand and Other Oceania  (see below for breakdown of countries)
Central, South and Other Americas  (see below for breakdown of countries)
Eastern Asia, Middle East and Other Asia  (see below for breakdown of countries)

 

Other Europe Tables 5 and 7 Includes the following countries:
Aland Islands	Greece	Montenegro
Albania	Guernsey	Poland
Andorra	Hungary	Portugal
Austria	Iceland	Romania
Belarus	Isle of Man	Russian Federation
Bosnia and Herzegovina	Jersey	San Marino
Bulgaria	Latvia	Serbia
Croatia	Liechtenstein	Slovakia
Cyprus	Lithuania	Slovenia
Czech Republic	Macedonia, The Former Yugoslav Republic of	Switzerland
Estonia	Malta	Turkey
Faroe Islands	Moldova, Republic of	Ukraine
Gibraltar	Monaco	Vatican City

 

Other Europe Table 9 Includes the following countries:
Aland Islands	Greece	Monaco
Albania	Guernsey	Montenegro
Andorra	Hungary	Portugal
Belarus	Iceland	Romania
Bosnia and Herzegovina	Isle of Man	Russian Federation
Bulgaria	Jersey	San Marino
Croatia	Latvia	Serbia
Cyprus	Liechtenstein	Slovakia
Czech Republic	Lithuania	Slovenia
Estonia	Luxembourg	Turkey
Faroe Islands	Macedonia, The Former Yugoslav Republic of	Ukraine
Finland	Malta	Vatican City
Gibraltar	Moldova, Republic of

 

Australia, New Zealand and Other Oceania Tables 5, 7 and 9 Includes the following countries:
American Samoa	Kiribati	Pitcairn
Australia	Marshall Islands	Samoa
Antarctica	Micronesia, Federated States of	Solomon Islands
Christmas Island	Nauru	South Georgia and the South Sandwich Islands
Cocos (Keeling) Islands	New Caledonia	Svalbard and Jan Mayen
Cook Islands	New Zealand	Tokelau
Fiji	Niue	Tonga
French Polynesia	Norfolk Island	Tuvalu
French Southern Territories	Northern Mariana Islands	United States Minor Outlying Islands
Guam	Palau	Vanuatu
Heard Island and McDonald Islands	Papua New Guinea	Wallis and Futuna

 

Other Areas Tables 5 and 7 Includes the following group of countries:
Central, South and Other Americas (See below for country breakdowns)
Africa (See below for country breakdowns)
Eastern Asia, Middle East and Other Asia (See below for country breakdowns)

 

Central, South and Other Americas Table 9 Includes the following countries:
Anguilla	Dominican Republic	Nicaragua
Antigua and Barbuda	Ecuador	Panama
Argentina	El Salvador	Paraguay
Aruba	Falkland Islands (Malvinas)	Peru
Bahamas	French Guiana	Puerto Rico
Barbados	Greenland	Saint Kitts and Nevis
Belize	Grenada	Saint Lucia
Bermuda	Guadeloupe	Saint Pierre and Miquelon
Bolivia	Guatemala	Saint Vincent and the Grenadines
Brazil	Guyana	Suriname
Cayman Islands	Haiti	Trinidad and Tobago
Chile	Honduras	Turks and Caicos Islands
Colombia	Jamaica	Uruguay
Costa Rica	Martinique	Venezuela
Cuba	Mexico	Virgin Islands, British
Dominica	Montserrat	Virgin Islands, US

 

Africa Table 9 Includes the following countries:
Algeria	Gambia	Rwanda
Angola	Ghana	Saint Helena
Benin	Guinea	Sao Tome and Principe
Botswana	Guinea-Bissau	Senegal
Burkina Faso	Kenya	Seychelles
Burundi	Lesotho	Sierra Leone
Cameroon	Liberia	Somalia
Cape Verde	Libya	South Africa
Central African Republic	Madagascar	South Sudan
Chad	Malawi	Sudan
Comoros	Mali	Swaziland
Congo	Mauritania	Tanzania, United Republic of
Congo, The Democratic Republic of the	Mauritius	Togo
Cote d'Ivoire	Mayotte	Tunisia
Djibouti	Morocco	Uganda
Egypt	Mozambique	Western Sahara
Equatorial Guinea	Namibia	Zambia
Eritrea	Niger	Zimbabwe
Ethiopia	Nigeria
Gabon	Reunion

 

Eastern Asia Table 9 Includes the following countries:
China	Korea, Republic of	Taiwan, Province of China
Hong Kong	Korea, Democratic People's Republic of
Japan	Mongolia

 

Middle East Table 9 Includes the following countries:
Afghanistan	Jordan	Qatar
Bahrain	Kuwait	Saudi Arabia
Iran, Islamic Republic of	Lebanon	Syrian Arab Republic
Iraq	Oman	United Arab Emirates
Israel	Palestinian Territory, Occupied	Yemen

 

Other Asia Table 9 Includes the following countries:
Armenia	Kazakhstan	Singapore
Azerbaijan	Kyrgyzstan	Sri Lanka
Bangladesh	Lao People's Democratic Republic	Tajikistan
Bhutan	Macao	Thailand
British Indian Ocean Territory	Malaysia	Timor Leste
Brunei Darussalam	Maldives	Turkmenistan
Cambodia	Myanmar	Uzbekistan
Georgia	Nepal	Vietnam
India	Pakistan
Indonesia	Philippines