In this blog you will read about the types and method of snowball sampling along with its advantages and disadvantages. 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. Snowball sampling article about snowball sampling by the. Munich personal repec archive a manual for selecting sampling techniques in research alvi, mohsin university of karachi, iqra university 23 march 2016 online at mpra paper no. Snowball sampling is a commonly employed sampling method in qualitative research, used in medical science and in various social sciences, including sociology, political science, anthro. Unlike convenience samples, research subjects are selected for specific attributes that preliminary research has defined as targets. Thus, this method is also called as the referral sampling method or chain sampling method. Snowball sampling is a technique used by researchers primarily when they are researching hidden populations or subcultures such as drug users. Probability sampling involves random selection, allowing you to make statistical inferences about the whole group. Nonprobability sampling is a sampling technique where the samples are gathered in a process that does not give all the individuals in the population equal chances of being selected.
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. Pdf snowball sampling is a wellknown, nonprobability method of survey sample. A manual for selecting sampling techniques in research. Using social media and targeted snowball sampling to. Snowball sampling is a popular technique among social scientists who wish to work with a population that is difficult to identify or locate.
In any form of research, true random sampling is always difficult to achieve. Assessing limitations and uses of convenience samples. Snowball sampling social research update university of surrey. Snowball definition in the cambridge english dictionary. Using this approach, a few potential respondents are contacted and asked whether they know of anybody with the characteristics that you are looking for in your research. This is a sampling technique, in which existing subjects provide referrals to recruit samples required for a research study. I will argue that when sampling methods are employed in qualitative research, they.
Comparision of snowball sampling and sequential sampling. Sampling is a procedure, where in a fraction of the data is taken from a large set of data, and the inference drawn from the sample is extended to whole group. Jan 26, 2017 judging by the numbers of views these two posts have accumulated it is clear that there is a demand for this type of discussion in a clear and concise manner. Aug 01, 2011 leo goodman 2011 provided a useful service with his clarification of the differences among snowball sampling as originally introduced by coleman 19581959 and goodman 1961 as a means for studying the structure of social networks. 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. Surveys of housing units, where an individual is asked who lives in the house, frequently misses some people.
This often occurs when the population is somehow marginalized, like homeless or formerly incarcerated individuals or those who are involved in illegal activities. This is a sampling technique in which existing subjects provide referrals to recruit samples required for a research study. Scholars have posited several anecdotally based recommendations for enhancing the diversity of snowball. A new approach to the study of hidden populations pdf. Researchers use this technique when the sample size is small and not easily available. While these projects define themselves as global surveys, the methodology they use, and particularly the sampling methods they apply, cast doubt on the. However, the use of the method is not adequately explained in most studies.
In probability sampling, the sampler chooses the representative to be part of the sample randomly, whereas in nonprobability sampling, the subject is chosen arbitrarily, to belong to the sample by the researcher. Snowball sampling is an approach for locating informationrich key informants1. It was used in lindesmiths original study of opiate addiction 1968 as well as in beckers work on marijuana smokers 1966. Snowball sampling is a wellknown, nonprobability method of survey sample selection that is commonly used to locate hidden populations. 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. You then ask them to recommend others who they may know who also meet the criteria. Purposive sampling is an informant selection tool widely used in ethnobotany table 1. One subject gives the researcher the name of another subject, who in turn provides the name of a third, and so on vogt, 1999. Purposeful sampling is widely used in qualitative research for the identification and selection of informationrich cases related to the phenomenon of interest. Snowball sampling in qualitative research sampling knowledge.
This method relies on referrals from initially sampled. Raj, p4 the surveyors a person or a establishment in charge of collecting and recording data or researchers initial task is to formulate a. I will attend to the snowball sampling procedure through qualitative and feminist sensibilities, so as to draw snowball sampling into or under more nuanced hermeneutics. Key informanta specific person that you believe will give you the most informationsometimes used to develop interview questions or to begin snowball sampling.
Systematic random sampling if a systematic sample of 300 students were to be carried out in ums with an enrolled population of 15,000, the sampling interval would be. I nn 15,000300 50 this meaning that 1 element student will be selected in every 50 students from the list of 15,000 ums students until the 300th student. Both of these works are typical in that they contain only sparse accounts of the sampling method. It is to this end that today i discuss another very popular method of sampling, known as snowball sampling. Traditional sampling methods are comprised of two elements 25, 26. Snowball sampling is where research participants recruit other participants for a test or study. Snowball sampling is a nonprobability sampling technique that is used by researchers to identify potential subjects in studies where subjects are hard to locate.
Target populations, sampling frames, and coverage error. Snowball sampling is a method of gathering information to access specific groups of people. Heterogeneity sampling is, in this sense, almost the opposite of modal instance sampling. In snowball sampling, you begin by identifying someone who meets the criteria for inclusion in your study. Snowball sampling is a special nonprobability method used when. Types of nonprobability random sampling quota sampling. Sep 19, 2019 there are two types of sampling methods. First, a full set of data sources is defined, creating. Difference between probability and nonprobability sampling. Sociology at surrey university of surrey research socialupdate. According to research mentioned in the paper written by kath browne, using social networks to research is accessible. Nonprobability sampling involves nonrandom selection based on convenience or other criteria, allowing you to easily collect initial data. Snowball sampling definition of snowball sampling by. Snowball sampling is a recruitment method that employs research into participants social networks to access specific populations.
In snowball sampling, the sample population is selected in a social context and in a multistage process, i. It allows the researcher to make asymptotically unbiased estimates from snowball samples under some conditions. The snowball sampling method has been derived from different concepts of social marketing. In other words, snowball sampling method is a good mechanism to obtain additional referrals from respondents to generate additional interview participants. One subject gives the researcher the name of another subject, who in turn. The strata is formed based on some common characteristics in the population data. This is not therefore a random sample and no inferences about the characteristics of the parent population can be made from such a study. Snowball sampling is a type of nonprobability sampling technique. These actors may themselves open possibilities for an expanding web of contact. Snowball sampling problems and techniques of chain referral sampling patrick blernackl sun francisco state university dan waldorf pacific institute for research and evaluation nowball or chain referral sampling is a method that has s been widely used in qualitative sociological research. The term snowball is used to represent a sampling method that relies on one participant recruiting friends and acquaintances from. Engaging marginalized populations in holistic research abstract womanist and feminist qualitative researchers continue to identify research methods and techniques that harness the power of social networking and personal connections while engaging with marginalized populations. Insights from an overview of the methods literature abstract the methods literature regarding sampling in qualitative research is characterized by important inconsistencies and ambiguities, which can be problematic for students and researchers seeking a clear and coherent understanding.
The current participants are asked to recommend new people for the study. Snowball sampling has been widely used in qualitative sociological research, especially in the. Snowball sampling is a type of convenience sampling method that is usually applied when it is difficult to acquire respondents with. A nonprobability sample obtained by recruiting one or more individuals who each recruit one or more individuals, and so on, in the manner of pyramid selling. Used to choose the number of participants, interviews, or work samples to use in the assessment process. The difference between probability and nonprobability sampling are discussed in detail in this article. Snowball sampling snowball sampling may simply be defined as. Division of academic and student affairs office of assessment sampling procedure 1 of 2 sampling procedure definition sample. Snowball sampling is a commonly employed sampling method in qualitative research. Its use is primarily in the collection of indepth, qualitative data, perhaps on sensitive topics, where an obvious. There is an element of convenience sampling in many qualitative studies, but a more thoughtful approach to selection of a sample is usually justified. The purposive sampling technique, also called judgment sampling, is the deliberate choice of an informant due to the qualities the informant possesses. 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.
Simple random sampling systematic random sampling stratified random sampling cluster sampling probability sampling methods compared nonprobabilitysamplingmethods availability sampling quota sampling purposive sampling snowball sampling lessonsaboutsamplequality generalizabilityinqualitative. Elvvs only to qualitative research, others have a much broader methodological significance. Snowball sampling is used in this research to reveal every actor involved in each case either directly or indirectly. Purposeful sampling for qualitative data collection and. For example, in the interview phase, snowball sampling can be used to reach hardtoreach populations. Nonprobability sampling research methods knowledge base. Most researchers are bounded by time, money and workforce and because of these. Convenience sampling saves time, money, and effort, but it is the least rigorous technique and may result in poor quality data and lacks intellectual credibility. This includes populations are such to social stigma and marginalization, such as suffers of aidshiv, as well as individuals engaged in illicit or illegal activities, including prostitution and drug use.
Snowball sampling or chainreferral sampling is defined as a nonprobability sampling technique in which the samples have traits that are rare to find. In this research, kath browne used social networks to research nonheterosexual women. Purposive sampling also known as judgment, selective or subjective sampling is a sampling technique in which researcher relies on his or her own judgment when choosing members of population to participate in the study. Enhancing the sample diversity of snowball samples plos. Snowball sampling is a useful choice of sampling strategy when the population you are interested in studying is hidden or hardtoreach. It is used where potential participants are hard to. Snowball sampling is defined as a nonprobability sampling technique in which the samples have traits that are rare to find.
In sociology and statistics research, snowball sampling is a nonprobability sampling technique. Broaden definition of who can be in sampling frame idea. Although it is sometimes used informally merely for convenience, it is also uniquely effective for accessing hidden groups scattered sparsely in large populations but linked by social networks, such as drug users, prostitutes. Pdf comparision of snowball sampling and sequential. Snowball sampling also called network, chain referral, or reputational sampling is a method for identifying and sampling the cases in a network. 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. From the listed the researcher has to deliberately select items to be sample. Snowball definition is a round mass of snow pressed or rolled together. The article provides the description and comparison of two nonrandom samplings which are snowball or chain referral sampling and sequential sampling.
Quota sampling, accidental sampling, judgemental sampling or purposive sampling, expert sampling, snowball sampling, modal instant sampling. The sampling method used for the survey was snowball sampling. 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 is a recruitment technique in which research participants are asked to assist researchers in identifying other potential subjects.
Purposive sampling is a nonprobability sampling method and it occurs when. Snowball sampling in qualitative research sampling. Stratified sampling is a type of sampling method in which the total population is divided into smaller groups or strata to complete the sampling process. Although there are several different purposeful sampling strategies, criterion sampling appears. The term snowball sampling has likely been in informal use for a long.
Snowball sampling helps researchers find a sample when they are difficult to locate. Snowball sampling or chainreferral sampling is defined as a a nonprobability sampling technique in which the samples have traits that are rare to find. Snowball sampling is a sampling technique to gather data or information from a specific group of people 27 and mostly used to study hidden population 28. Enhancing the sample diversity of snowball samples. Using social media and targeted snowball sampling to survey a. Snowball sampling definition in the cambridge english. Snowball sampling or chainreferralsampling of a hidden population begins with a convenience sample of initial subject, because if a random sample could be drawn, the population would not restrict as 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. Nonprobability sampling is a sampling procedure that will not bid a basis for any opinion of probability that elements in the universe will have a chance to be included in the study sample. However, people who are involved in research studies and have educational opportunities should always consider individual rights and privacy. Sampling from populations in which individuals are hard to identify can justify clever approaches, but the role of the simple random sampling model in.
Often the meaning of a term evolves over time, or di. Broaden the definition of who can be in the sampling frame, then screen out as necessary incurs extra costs and requires additional effort example. It begins with one or a few people or cases and spreads out on the basis of links to the initial cases. 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. A manual for selecting sampling techniques in research 4 preface the manual for sampling techniques used in social sciences is an effort to describe various types of sampling methodologies that are used in researches of social sciences in an easy.
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