Hang-ups-Looking in ~ Non-Response in call Surveys
Nancy McGuckin Travel behavior Analyst/NHTS Team Member Nancy.McGuckin
Since the mid-1980"s, telephone surveys have become the standard practice for obtaining data on family travel in the U.S. (Stopher, 1996). But, for a range of factors including alters to the north American telephone numbering system, the accessibility of intercepting technologies, such together caller-ID, and the multiple contacts required to finish a two-stage survey, telephone-based travel surveys seem come be enduring from declining an answer rates. Recent regional telephone surveys that household activity or travel surveys in the U.S. Have had actually household solution rates varying from 20 come 40 percent (Zimowski, Tourangeau et al, 1997).
The info presented in this paper was obtained from the pretest that the National household Travel inspection (formerly the NPTS/ATS). The 2000 pre-test included a number of technique and content tests, but for this study we check the check of nine call attempts matches nineteen contact attempts and the imbedded non-response follow-up survey. Because that the pre-test together a whole, the household recruitment rate (called the teamwork rate in this paper) was 44 percent, and the final response rate to be 28 percent. This an extremely low solution rate motivated a hard look at wherein we lost potential respondent in the survey process.
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Non-response is made up of refusals and also non-contacts. We have used the call-disposition file (a tally that the outcomes of each attempt to call each household) and also the non-response follow-up inspection to shot and understand more about non-response. Indigenous the speak to disposition document we have uncovered that non-contact is a much larger area of loss than direct refusal. Because that example, almost 30 percent of contact attempts got to an answering machine, and also never contacted a person. An additional 25 percent of contact attempts rang v no answer.
When response rates autumn low enough, questions around the representativeness that the respondents room raised. This is most likely the biggest challenge facing telephone-based and also random-digit dialing (RDD) surveys. As contact rates and solution rates fall, inspection practitioners should take into consideration a variety of methods to rise contact and participation.
One the the biggest dilemmas confronted by inspection practitioners in the US this day is weighing the services of CATI (computer assisted telephone interviewing) through an RDD (random number dialing) sample frame compared to the serious declining solution rates for this method. The CATI/RDD technique for large-scale surveys obtained popularity in the U.S. Transparent the 1970"s and also by the finish of the 1980"s also some really traditional government agencies had switched from attend to samples to RDD. The services of the phone call contact, using an RDD sample, contrasted to an resolve sample, include:Lower cost per survey unit in a CATI/RDD survey enables for a much larger sample size. intricacy of the questionnaire and also issues developing from actual interviews are dealt with effectively since CATI modern technology allows because that automated skip patterns and on-line edits. A centralized interviewer pool allows for much more training and also interviewer feedback The telephone together the call instrument enables for an ext contact attempts and much higher variation in time contacts space attempted. In the us potential respondent in some neighborhoods were getting an ext and an ext wary of having actually interviewers present up at your door.
However, in the U.S. Recently we show up to be dealing with a serious decline in an answer rates with this method. World have come to be wary the telephone solicitation and find it easy to hang-up the telephone. Families are busy and resent intrusions top top their home time. Probably the distrust of government has increased, as have actually concerns around privacy.
Some researchers space looking in ~ the presumptions integral come the CASRO conventional of computing response rates, such together the assumption that non-contacts room proportionally similar to contact in regards to eligible units. Part researchers proceed to look because that methodological approaches, such as pre-contact letter to legitimize the survey, an extremely intensive contact attempts (one commonwealth survey will certainly attempts every number up to 40 times), and multiple settings of contact.
In addition, the use of one RDD sample is further complicated by transforms in the telephone industry, such together the practically six-fold boost in the number of potential telephone number in the time in between 1990 and also 2000, greater ease of access of cabinet phones, and also multiple present in countless residences.
In this research study we looked at non-contacts and refusals by utilizing the contact disposition document (which tallies the results of each contact attempt to every sample number), and the non-response follow-up survey imbedded in the pretest.
The contact disposition file is a rich resource of information yet cumbersome to analyze. Details on each speak to attempt allows us to save track of call patterns and telephone comment behavior, and also potentially to connect contact fads to final outcomes. For example, part intriguing research study in politics opinion surveys (Couper 1997) uncovered that civilization who said they were not interested in participating, yet later completed, had an extremely different political mindsets then those who readily agreed to participate. Follow-up research study linking the contact behavior to take trip patterns might discern comparable biases.
2. Alters in the Sampling Frame
There has been significant discussion in the industry research field about the changes in the U.S. Phone call sample frame. The development in phone call exchanges because of telephone agency competition, the relax of telephone number from geography (called portability), the proliferation that multi-line households, the projected surge in moving phones as a main residential phone call have complex the picture even more.
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In addition, the many obstacles to contacting a person continues to concern practitioners, as use of one answering maker grows in accept and an ext and more methods of screening calls are easily accessible to the telephone user. Speak to identifying technologies, such as caller-ID and privacy guard, as well as multi-use phone call lines, boost the an obstacle of identify an eligible family members from the RDD sample.
These comes to focus on two things: fishing because that residential numbers in a more dispersed cosmos of working eligible samples, and barriers to call a potential respondent via the phone call line. The concerns around the sample frame flourish from the proliferation that exchanges, which consequently lowers the family "hit" rate, and likewise brings into question some of the methods used to increased sample efficiency (such together sampling just blocks whereby at the very least one number is listed). The proliferation that exchanges and also the impact on the probability of connecting with a working residential phone are shown in Table 1.