Snowball sampling is a type of nonprobability sampling technique. Snowball or chain sampling involves utilizing well informed people to identify critical cases or informants who have a great deal of information about a phenomenon. 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. Snowball sampling definition of snowball sampling by.
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. Sampling background 10 minutes assumption, definition, objectives network sampling methods full access, restricted access, streaming access estimating nodal or edge characteristics 30 minutes sampling representative subnetworks 30 minutes sampling and counting of substructure of networks 30 minutes. Because it is a snowball sampling technique, the number of potential publications gathered at each level increases exponentially and can grow quite large. Statistical methods sampling techniques statstutor. Unlike convenience samples, research subjects are selected for specific attributes that preliminary research has defined as targets. In statistical sampling probability sampling technique calculating the probability of getting. The total target land is divided into mutually exclusive sections, then list of housing is made in each section, and then samples are drawn from this list. Introduction since the earliest applications of quota sampling in the early twentieth century, there has been a wealth of references to its unsuitability for some purposes, such as to obtain populationrepresentative samples 16. As the sample builds up, enough data are gathered to be useful for.
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. However, defining sampling units clearly before choosing cases is essential in order to avoid messy and empirically shallow research. Its only advantage over the random sampling technique is simplicity. 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. This type of sampling technique is also known as purposive sampling and authoritative sampling.
As a matter of fact, in contemporary organizational research the problem of representativeness is a. Sociology at surrey university of surrey research socialupdate. It is useful when the investigator may not have access to a population of potential subjects who meet inclusion criteria, which may often be stigmatizing. On estimating the scale parameter of the selected uniform population under the entropy loss function arshad, mohd. Appendix iii is presenting a brief summary of various types of nonprobability sampling technique. The sampling rate is controlled purely for the sake of keeping the data collection manageable. The purposive sampling technique, also called judgment sampling, is the deliberate choice of an informant due to the qualities the informant possesses. 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. Target population does not have equal chance of being selected, the. Snowball sampling in qualitative research sampling. Design for the control of selection bias blackwell, david and hodges, j. Snowball sampling snowball sampling is a recruitment method in which an investigator enlists the help of a research subject in identifying, and possibly recruiting, additional subjects. The words that are used as synonyms to one another are mentioned. 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.
Thus, this method is also called as the referral sampling method or chain sampling method. Snowball sampling the sampling methods royalty free vector. Systematic sampling is frequently used to select a specified number of records from a computer file. Sampling can either be statistical or nonstatistical. In statistical sampling, workforce, time and money highly limits most. This referral technique goes on and on, increasing the size of the respondent population like a snowball rolling down a hill until the researcher. Convenience sampling is a type of nonprobability sampling. Snowball sampling from a citation network at three levels. 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. Purposive sampling as a tool for informant selection. We are going to see from diverse method of five different sampling considering the non. Snowball or chain sampling qualitative research guidelines. Using social media and targeted snowball sampling to survey a.
Pdf comparision of snowball sampling and sequential. In my time as an academic i have come across many proposals, articles, workshop papers and seminars which. The term snowball is used to represent a sampling method that relies on one participant recruiting friends and. 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. 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. Sampling the process of using a small number of items or parts of larger population to make a conclusions about the whole population.
Using social media and targeted snowball sampling to. Purposive sampling is used in cases where the specialty of an authority can select a more. The article provides the description and comparison of two nonrandom samplings which are snowball or chain referral sampling and sequential sampling. Qualitative researchers typically make sampling choices that enable them to deepen understanding of whatever phenomenon it is that they are studying. Since the cadre of the target sample group was so high, it would be more effective to follow the snowball sampling technique sedgwick, 20.
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. This article explains a what snowball sampling is, b how to create a snowball. Snowball or chain sampling is the most common form of purposeful sampling. In the past i have spoken about some of these in detail, for example i mention and discuss from a holistic perspective what is sampling, and why as a concept it is extremely important.
The variables to which the sample is drawn up are linked to the research question. As described in leo goodmans 2011 comment, snowball sampling was developed by coleman 19581959 and goodman 1961 as a means for studying the structure of social networks. The researcher follows this chain of contacts in order to identify and accumulate critical cases. Thus the sample group is said to grow like a rolling snowball. Sampling methods, random sampling, multistage cluster sampling, random route method, quota sampling 1. Stratified sampling is commonly used probability method that is superior to. 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. One subject gives the researcher the name of another subject, who in turn provides the name of a third, and so on vogt, 1999. However, the use of the method is not adequately explained in most studies. In statistical sampling probability sampling technique calculating the probability of getting any particular sample is possible. In this, geographical selection of population is done. This method relies on referrals from initially sampled.
Selecting samples population, sample and individual cases source. 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. Goodmans formulation requires an initial sample drawn using a probability method on a known sampling frame. If youre interested in researching a specific group of people, like restaurant managers or crime victims, you need to recruit participants for your study. Jan 26, 2017 in other words, snowball sampling method is a good mechanism to obtain additional referrals from respondents to generate additional interview participants. The way that the sample is chosen by target people makes it liable to. On twostage nonparametric estimation yen, elizabeth h. Snowball sampling is a popular technique among social scientists who wish to work with a population that is difficult to identify or locate. Multiple choice questions try the multiple choice questions below to test your knowledge of this chapter. Snowball sampling is a type of convenience sampling method that is usually applied when it is difficult to acquire respondents with target characteristics naderifar et. It involves locating relevant organizations and experts who are knowledgeable about a given research. Sampling is done on the basis of predetermined idea clinical knowledge. 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. Some remarks on systematic sampling gautschi, werner, annals of mathematical statistics, 1957.
Several years after colemans and goodmans development of snowball sampling, what was also termed snowball sampling emerged as a. Snowball sampling is a technique used by researchers primarily when they are researching hidden populations or subcultures such as drug users. It is useful when the researcher know little about a group or organisation. Ch7 sampling techniques university of central arkansas. There are many many different ways to develop your sampling strategy. A subgroup of the whole population is selected for data collection e. When subjects of specific characteristics are hard to locate. The population to be studied to which the investigator wants to generalize his results sampling unit. Every member of the population is equally likely to be selected. Purposive sampling is an informant selection tool widely used in ethnobotany table 1.
Once you have completed the test, click on submit answers for grading to get your results. Both methods categorize the target population into a certain number of groups. 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. Judgmental sampling is a nonprobability sampling technique where the researcher selects units to be sampled based on their knowledge and professional judgment. In sociology and statistics research, snowball sampling 1 or chain sampling, chainreferral sampling, referral sampling 2 3 is a nonprobability sampling technique where existing study subjects recruit future subjects from among their acquaintances. Some fixedsample ranking and selection problems mahamunulu, d. Creating a snowball sample to create a snowball sample, there are two steps. Snowball sampling or chainreferral sampling is defined as a nonprobability sampling technique in which the samples have traits that are rare to find. Comparision of snowball sampling and sequential sampling technique. Comparision of snowball sampling and sequential sampling. 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.
Define nonprobability sampling, and describe instances in which a researcher might choose a nonprobability sampling technique. Snowball sampling snowball sampling may simply be defined as. Understanding the complex components of communitybased. Snowball sampling is a nonprobability sampling technique that is used by researchers to identify potential subjects in studies where subjects are hard to locate. A manual for selecting sampling techniques in research. Calculating the confidence interval for a mean using a formula statistics help duration. Snowball sampling is a recruitment technique in which research participants are asked to assist researchers in identifying other potential subjects. The manual for sampling techniques used in social sciences is an effort to describe. Business and marketing or social research process, snowball sampling is a nonprobability sampling technique in qualitative research. Convenience sampling is not preferred way of sampling for effective analysis as samples are taken from specific section of the population. In the section which sampling technique to use in your research. Snowball sampling research office oregon state university. This is a particularly interesting dimensionone that is unique to chain methods of samplingwhich carries far reaching consequences, to be discussed in terms of social capital and reproduction of social systems bourdieu, 1986 and giddens, 1984, respec.
Snowball sampling has been widely used in qualitative sociological research, especially in the. Nonprobability and probability sampling techniques a. Thus the sample group appears to grow like a rolling snowball similarly to breadthfirst search bfs in computer science. Aspects of snowball chain sampling, unique sampling, and maximum variation sampling were used for this thesis. Snowball sampling in qualitative research sampling knowledge. 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. The need to samplesampling a valid alternative to a census. This often occurs when the population is somehow marginalized, like homeless or formerly incarcerated individuals or those who are involved in illegal activities. Aspects of snowballchain sampling, unique sampling, and maximum variation sampling were used for this thesis. It is scientific and every element stands an equal chance of being selected. The technique is a kind of statistically non representative stratified sampling because, while it is similar to its quantitative counterpart, it must not be seen as a sampling strategy that allows statistical generalisation to the large population. Typical individuals are selected who are believed to be representative of a larger group.
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. Describe the different types of nonprobability samples. Often a few key informants or cases will be mentioned multiple times and take on. Nonprobability sampling unequal chance of being included in the sample nonrandom non random or non probability sampling refers to the sampling process in which, the samples are selected for a specific purpose with a predetermined basis of selection.
Snowball sampling is a wellknown, nonprobability method of survey sample selection that is commonly used to locate hidden populations. When you are asked to survey about the habit of drinking alcohol in your town, you will not go and roam all around. A key advantage of stratified sampling is that it randomly selects elements in every stratum. In other words, the sample starts small but snowballs into a larger. 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. Likewise, the module on tabulation module 4 contains instructions for producing standard labour market statistics, such as the unemployment rate, that researchers can use for any number. The discrete case sackrowitz, harold, annals of mathematical statistics, 1970. Can do a better job of data collection when its impossible to study the whole population target population. Snowball sampling is a nonprobability based sampling technique that can be used to gain access to such populations. A manual for selecting sampling techniques in research munich. Aug 07, 2017 calculating the confidence interval for a mean using a formula statistics help duration.
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