Are all U.S. gateway airports represented in the monthly survey?
No. However, in 2008 NTTO
collected responses in the gate areas of, or on flights departing from, 30 U.S. gateway airports which accounted for 97% of all overseas air traffic. The issue is not the number of gateways, but whether the number of collections in each gateway is optimum. Some gateways are under-surveyed (Miami) and some are over-surveyed (JFK). Our objective is to correct this. See the next question.
Are all international air carriers represented in the monthly samples?
No. However, the 80 + carriers from which we collected responses, either on-board or in the gate area, accounted for about 95% of all air traffic departing the U.S. As with airports, the issue centers on the optimum number of collections per carrier per overseas region served, as well as at each gateway. To date, there is only one carrier that has specifically declined to be in the Survey. Two very large carriers are being under-sampled. So the number of carriers is not the issue as much as the proportionate distribution among the participants. Since the overall participation of the in-flight method has been on the wane we have initiated the Supplemental Airport Survey Program to enhance collections, to match airline traffic levels, at specific airports, i.e. Philadelphia, Atlanta, Orlando and Denver.
Are the Survey data valid?
The Survey measures what it is suppose to measure (the statistical definition of the term, validity), namely the characteristics and perceptions of international travelers to and from the U.S.
Are the Survey data reliable?
The Survey produces very stable results where we have robust sample sizes, i.e., at the national level and from the top 20 origin countries producing visitors. It is at the sublevel of country/destination, a/k/a the origin-destination level, that the VOLUME estimates get ‘ jumpier’, when compared year-over-year due to smaller sample sizes and normal sampling error.
Are the Survey data accurate?
An estimate is accurate when compared favorably to a known and proven outcome. Currently there is no other known public method that produces an accurate outcome. However, the raw Survey data is modified, through a weighting methodology, to comply with the known accurate census of non-resident arrivals to the U.S., the DHS I-94 Arrival Record and U.S resident departures via the DHS I-92.
Why has NTTO’s Survey methodology remained the same?
In fact it has changed. NTTO has continually sought innovative approaches since the inception of the Survey program in 1983. More recently, in 2005 NTTO issued a Request for Information (RFI) and a follow-on Request for Proposals (RFP). The RFP repeatedly emphasized the invitation for new and innovative approaches. That CIC Research, Inc. was awarded the new contract reflects—literally—that either all bidders proposed the same approach or that CIC’s approach was determined best by the judging panel. In 2008, NTTO and CIC conducted an e-Survey trial using the internet and CRS booking engines. While that approach showed some promise it did not prove to be cost efficient. We are currently researching the possibility of using aircraft in-flight entertainment (IFE) systems and/or internet connections to deliver and collect survey data.
Why isn’t a probability sample selected from all foreign residents on each departing flight? It appears that no attempt is made to select a random sample of passengers within each flight. If this cannot be done, questionnaires should be passed out to all adult passengers on the flight or distributed to all adult passengers waiting at the airport departure gate, and high response rates encouraged.
For an in-flight random selection, cooperation would be needed from both airline management and the flight crew. In general, and as an understatement, contract employees are not readily compliant with duties not covered in their labor agreements. Airline managers are openly adverse to actions they perceive to be detrimental to customer service. Of the 15 participating in-flight carriers thirteen are foreign based carriers, one of which does in fact select passengers in a random method. Of the 55+ carriers that we survey in the gate area one could argue that selection is in effect random given the mobility of the passengers in the gate area. Also, it would be impractical to consider surveying the entire population given the magnitude of 25.8 million non-resident overseas travelers on 527,000 flights during 2007. This program operates with funding constraints.
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