For example, respondents who have many links are more likely to be recruited into the sample. As the sample builds up, enough data are gathered to be useful for. In sociology and statistics research, snowball sampling or chain sampling, chainreferral sampling, referral sampling is a nonprobability sampling technique where existing study subjects recruit future subjects from among their acquaintances. Unlike convenience samples, research subjects are selected for specific attributes that preliminary research has defined as targets. In taking a sample of villages from a big state, it is more administratively convenient to consider the districts as strata so that the administrative set up at district level may be used. The methods of statistical inference applied to the data obtained from an s. The snowball sampling is a nonrandom sampling technique wherein the initial informants are approached who through their social network nominate or refer the participants that meet the eligibility criteria of the research under study. Snowball sampling also known as chainreferral sampling is a nonprobability nonrandom sampling method used when characteristics to be possessed by samples are rare and difficult to find. Firstly, and most easily, as an informal method to reach a target population. This article explains a what snowball sampling is, b how to create a snowball. Thus, this method is also called as the referral sampling method or chain sampling method.
Assessing limitations and uses of convenience samples. Tawan chalalai 59376568 nadcha lujintanon 5937623438 nissareen veerasatien 5937615438 inchnok lewchalermwongse 5937652638. In the ambit of social research, the use of new technologies is still questioned because the selection bias is an obstacle to carry on scientific research on the internet. Beginning with the premise that research is formed, the paper offers one account of snowball sampling and using social networks to make research. In snowball sampling, the sample population is selected in a social context and in a multistage process, i. Snowball sampling is a nonprobability sampling technique that is used by researchers to identify potential subjects in studies where subjects are hard to locate. Heckathorn 1997, 2002 and salganik and heckathorrn 2004 address respondent driven sampling, a form. It was widely believed that it was impossible to make unbiased estimates from snowball samples, but a variation of snowball sampling called respondentdriven sampling has been shown. Enhancing the sample diversity of snowball samples. Sociology at surrey university of surrey research socialupdate. Snowball sampling or chainreferral sampling is defined as a a nonprobability sampling technique in which the samples have traits that are rare to find. The snowball metaphor relates to the fact that the study expands, using additional participants gathered from the original sample subjects and provides further elements for study of the subject. It is useful when the researcher know little about a group or organisation. This method relies on referrals from initially sampled.
The aim of this paper is to present a sampling method using virtual networks to study hard. A manual for selecting sampling techniques in research. Snowball sampling is a special nonprobability method used when. This is a sampling technique, in which existing subjects provide referrals to recruit samples required for a research study for example, if you are studying the level of customer satisfaction among the members.
The snowball sampling method is extensively used where a population is unknown and rare and it is tough to choose subjects to assemble them as samples for research. While in sequential sampling, sampling was taken at a given time interval and modification can be made by. Snowball sampling may be defined as a technique for gathering research subjects through the identification of an initial subject who is used to provide the names of other actors. Snowball sampling or chainreferral sampling is defined as a nonprobability sampling technique in which the samples have traits that are rare to find. The article provides a descripton and analysis of some of theproblems that were encountered and resolved in the course of using the method in a relatively large exploratory study of exopiate addicts. Let us see a few examples of global surveys and note the problematic i just mentioned. Quota sampling is a nonprobability sampling technique wherein the assembled sample has the same proportions of individuals as the entire population with respect to known characteristics, traits or focused phenomenon. This method relies on referrals from initially sampled respondents to other persons believed to have the characteristic of interest. Snowball sampling is often used because the population under investigation is hidden either due to low numbers of potential participants or the sensitivity of the topic, for example. In some situations where, for example, the variance of this ratio is near zero, mathematical results obtained for binomial sampling are sometimes quite similar to results obtained using some of the more usual sampling models see 4, 7.
Quota sampling applied in research nonprobability sampling. A type of purpose sampling where existing participants recruit future subjects from among their acquaintances. For example, if you are studying the level of customer satisfaction among elite nirvana bali golf club in bali, you will find it increasingly difficult to find primary data sources unless a. This referral technique goes on and on, increasing the size of the respondent population like a snowball rolling down a hill until the researcher. It also talks in detail about probability sampling methods and nonprobability sampling. Snowball sampling is often used in hidden populations which are difficult for researchers to access.
Common examples of the use of snowball sampling involve sociological studies into hidden populations that may be involved in sensitive issues or illegal activities, such as drug use and prostitution. In other words, snowball sampling method is a good mechanism to obtain additional referrals from respondents to generate additional interview participants. Snowball sampling johnson 2005 major reference works. Snowball sampling has been widely used in qualitative sociological research, especially in the study of deviant behavior and is used in the place where the population is hard to reach. Snowball sampling uses a method beloved by sales people, where customer referrals to new prospects have particular value as the relationship of trust and obligation between the identified person and the referrer makes it more likely that the new person will make a purchase. As is typical of terms adopted by a variety of fields, however, the phrase snowball sampling is used inconsistently across. Snowball sampling is a recruitment technique in which research participants are asked to assist researchers in identifying other potential subjects. The student researcher will see facebook as providing an opportunity to obtain a large sample of data inexpensively, but not without raising questions of possible bias. This approach allows you to utilise the original group as informants who can help in identifying additional people to interview who qualify for inclusion and these, in turn, identify yet. Comparision of snowball sampling and sequential sampling. Sampling is defined as the process of selecting certain members or a subset of the population to make statistical inferences from them and to estimate characteristics of the whole population. Enhancing the sample diversity of snowball samples plos.
Snowball sampling research office oregon state university. For example, if you wanted to interview a sample of vegetarians cyclists people with a particular. It also described different form of sampling method. Administrative convenience can be exercised in stratified sampling. For example, when s k 1, the number, ml, of mutual relationships present in the population i. Thus the sample group is said to grow like a rolling snowball. Pdf snowball sampling is a wellknown, nonprobability method of survey sample selection that is commonly used to locate hidden.
Researchers use this sampling method if the sample for the study is very rare or is limited to a very small subgroup of the population. This article attempts to rectijy this methodological neglect. This is a sampling technique, in which existing subjects provide referrals to recruit samples required for a research study for example, if you are studying the level of customer satisfaction among the. Pdf comparision of snowball sampling and sequential. Estimation of population totals by use of snowball samples, in perspectives on. This article enlists the types of sampling and sampling methods along with examples. For example a population of schools of canada means all the schools built under the boundary of the country. Using social media and targeted snowball sampling to.
The term snowball sampling has been applied to two. Sampling theory chapter 4 stratified sampling shalabh, iit kanpur page 7 3. Snowball sampling is a commonly employed sampling method in qualitative research, used in medical science and in various social sciences, including sociology, political science, anthropology and human geography. Snowball sampling has been widely used in qualitative sociological research. Media and targeted snowball sampling 282 ples and the asystematic recruitment of research subjects in convenience samples on the one hand and the more rigid cluster and stratified samples on the other. Snowball sampling is a wellknown, nonprobability method of survey sample selection that is commonly used to locate hidden populations. Snowball sampling is a commonly employed sampling method in qualitative research. In sociology, snowball sampling refers to a nonprobability sampling technique which includes purposive sampling in which a researcher begins with a small population of known individuals and expands the sample by asking those initial participants to identify others that should participate in the study. Snowball sampling is a technique where a researcher picks the first few samples and either recruits them or asks them to recommend other subjects they know who fit the description of samples needed. Therefore, if the number of students in the course population is a course in this example is between 25100, then use the entire student population for that course.
Snowball sampling can be applied for two primary purposes. Snowball sampling friend of friend you initially contact a few potential respondents and then ask them whether they know of anybody with the same characteristics that you are looking for in your research. Snowball sampling has been widely used in qualitative sociological research, especially in the. This technique relies on existing study participants. The use of currently enrolled research participants to recruit additional research participants sometimes referred to as the snowball sampling may be approved by the irb under some circumstances. A manual for selecting sampling techniques in research 10 population and a sample population target population refers to all the members who meet the particular criterion specified for a research investigation. In this regard, the authors hypothesis is that the use of social networking sites web.
In other words, the sample starts small but snowballs into a larger. In other words, the sample starts small but snowballs into a larger sample through the. For example, if you are studying the level of customer satisfaction among elite nirvana bali golf club in bali, you will find it increasingly difficult to find primary data sources unless a member is. Snowball sampling is a special nonprobability method used when there are difficulties in identifying members of the population or if the desired sample characteristic is rare.
Snowball sampling is a type of nonprobability sampling technique. Although they violate the principles of sampling, the use of snowball strategies provides a means of. Statistical inferences can be drawn from the zerostage of a snowball sample. This is a sampling technique, in which existing subjects provide referrals to recruit samples required for a research study. Pdf comparision of snowball sampling and sequential sampling. If youre interested in researching a specific group of people, like restaurant managers or crime victims, you need to recruit participants for your study. Snowball sampling social research update university of surrey. Nonprobability sampling focuses on sampling techniques that are based on the judgement of the researcher see our article nonprobability sampling to learn more about nonprobability sampling.
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