Web Survey Bibliography
Title Access pools as a solution to the nonresponse problem?
Author Stoop, I.
Access date 13.09.2004
Abstract As obtaining high response rates is increasingly difficult, an increasing number of organisations revert to so-called access pools as a means to ensure high response rates. Access pools are groups of people who have agreed to regularly participate in future surveys run by a specific organizations, generally a market research organization. For a survey among an access pool, a either a sample is drawn from a pool of cooperative individuals or households that is similar to the general population on socio-demographic characteristics, or a specific sample is selected, for instance parents of small children in rural areas. The latter possibility to select specific subgroups, makes it a very attractive instrument. Access pools are nowadays more and more web access pools. Access pools can be based on probability sampling and on nonprobability sampling. The former are also called pre-recruitment panels, the latter volunteer panels. In pre-recruitment panels recruitment is passive. At the end of each survey run by a market research organization, for instance, respondents are asked if they want to be an access pool member, and after each survey the pool gets larger. If the recruitment is from random sample surveys, and information on initial inclusion probabilities and response rates are available (which is rarely the case), a survey among (a random sample from) an access pool can theoretically be considered as based on probability sampling. If inclusion probabilities and nonresponse in earlier phased are unknown, and if there is a large attrition in earlier phases, the probability character of access pools is easily lost. In volunteer pools recruitment is active: respondents can apply for membership of an access pool. If respondents can self-select, it is definitely a non-probability sample, and actually quite similar to a quota sample (provided there are controls on pool membership or controls on selecting pool members for a survey). Access pools have a number of advantages. Firstly, nonprobability samples generally have higher response rates than probability samples and particularly access pools have high response rates. Market research organizations even tout customers for their access pools with the recommendation that high response rates are guaranteed, because the respondents (here: members of the access pool) have stated that they are willing to participate in surveys. A second advantage is that both quota samples and access pools can be made ‘representative’ a priori and that weighting for under-represented groups (because of sampling errors and nonresponse) is not necessary any more. This is related to the third advantage, namely that special groups (homosexuals, parents of young children) can easily be selected from access pools as many characteristics of the pool members are known, or because screening is relatively inexpensive. The fourth advantage is that the turnaround time of quota samples and access pools is generally shorter than for random samples. In the latter case, many calls have to be made to contact a sample household (in face-to-face surveys), mail reminders have to be sent, and initial refusers have to be converted. When using quota sampling, not much time has to be spent on including a particular sample person, as any other with the same characteristics will do. In access pools, respondents are interested and willing to participate, so obtaining response goes fast too. The final advantage is related to the previous ones: they are often less expensive than random samples. This may partly be due to the fact that access pools generally use web or mail surveys. They are presumably also less expensive, because pool members have promised to regularly partake in surveys, and therefore less time has to be devoted to persuading respondents to participate. On the other hand, maintaining a pool requires time and money too. The paper will discuss the assumptions behind access panels, the meaning of representativeness, the possibility of statistical inference from access panels, comparisons between access pools and random samples and the question whether access pools can solve the nonresponse problem.
Access/Direct link Homepage - conference (abstract)
Year of publication2004
Bibliographic typeConferences, workshops, tutorials, presentations
Web Survey Bibliography - Stoop, I. (11)
- Unit Non-Response Due to Refusal; 2012; Stoop, I.
- Classification of Surveys; 2012; Stoop, I., Harrison, E.
- Smartphone Data Collection Among LISS Panel Members; 2011; Fernee, H., Sonck, N., Stoop, I.
- Nonresponse Bias in Surveys; 2009; Bethlehem, J., Vehovar, V., Stoop, I., Schouten, B., Shlomo, N., Skinner, C., Montaquila, J.
- Access panels and online research, panacea or pitfall? Proceedings of the DABS symposium, Amsterdam,...; 2008; Stoop, I.
- Survey data, context and event data; 2007; Stoop, I.
- Increased fieldwork efforts, enhanced response rates, better estimates?; 2007; Stoop, I., Verhagen, J., van Ingen, E.
- Online Panels - A Paradigm Theft? ; 2007; Bethlehem, J., Stoop, I.
- Access Panels and Survey Nonresponse: Making It Better or Worse?; 2007; Stoop, I., Bethlehem, J., de Bie, S.
- The Impact of Events on Attitudes: Real-time Measurement; 2007; Stoop, I.
- Access pools as a solution to the nonresponse problem?; 2004; Stoop, I.