Editing Snowball sampling (section)

==Advantages and disadvantages==

===Advantages===
# '''Locate hidden populations''': It is possible for the surveyors to include people in the survey that they would not have known but, through the use of social network.
# '''Locating people of a specific population''': There are no lists or other obvious sources for locating members of the population (e.g. the homeless, users of illegal drugs). The investigators use previous contact and communication with subjects then, the investigators are able to gain access and cooperation from new subjects. The key in gaining access and documenting the cooperation of subjects is trust. This is achieved that investigators act in good faith and establish good working relationship with the subjects.
# '''Methodology''': As subjects are used to locate the hidden population, the researcher invests less money and time in sampling. Snowball sampling method does not require complex planning and the staffing required is considerably smaller in comparison to other [[Sampling (statistics)|sampling methods]].<ref name="Mirela2">{{cite journal|date=2011|title=Using the Snowball Method in Marketing Research on Hidden Populations|journal=Challenges of the Knowledge Society|volume=1|pages=1341–1351|last1=Voicu|first1=Mirela-Cristina}}</ref>

Snowball sampling can be used in both alternative and complementary research methodologies. As an alternative methodology, when other research methods can not be employed, due to challenging circumstancing and when random sampling is not possible. As complementary methodology with other research methods to boost the quality and efficiency of research conduct and to minimize the sampling bias like [[quota sampling]].<ref name="Cohen 423–435"/><ref>{{cite web|url=http://sru.soc.surrey.ac.uk/SRU33.html|title=Social Research Update 33: Accessing Hidden and Hard-to-Reach Populations|website=sru.soc.surrey.ac.uk|access-date=2017-04-02}}</ref>

===Disadvantages===

# '''Community bias''': The first participants will have a strong impact on the sample. Snowball sampling is inexact and can produce varied and inaccurate results. The method is heavily reliant on the skill of the individual conducting the actual sampling, and that individual's ability to vertically network and find an appropriate sample. To be successful it requires previous contacts within the target areas, and the ability to keep the information flow going throughout the target group.<ref>{{cite web|url=https://research-methodology.net/sampling-in-primary-data-collection/snowball-sampling/|title=Snowball sampling}}</ref>
# '''Non-random''': Snowball sampling contravenes many of the assumptions supporting conventional notions of random selection and representativeness.<ref>{{cite book|last1= Atkinson|first1= Rowland | last2=Flint | first2=John | year=2004 |title=Encyclopedia of Social Science Research Methods |isbn= 9780761923633 | pages= 1044–1045|publisher= SAGE Publications, Inc.}}</ref> However, social systems are beyond researchers' ability to recruit randomly. Snowball sampling is inevitable in social systems.
# '''Unknown sampling population size''': There is no way to know the total size of the overall population.<ref name="Morgan"/>
# '''[[Anchoring]]''': Another disadvantage of snowball sampling is the lack of definite knowledge as to whether or not the sample is an accurate reading of the target population. By targeting only a few select people, it is not always indicative of the actual trends within the result group. Identifying the appropriate person to conduct the sampling, as well as locating the correct targets is a time-consuming process such that the benefits only slightly outweigh the costs.
# '''Lack of control over sampling method''': As the subjects locate the hidden population, the research has very little control over the sampling method, which becomes mainly dependent on the original and subsequent subjects, who may add to the known sampling pool using a method outside of the researcher's control.

===Compensations===

The best defense against weaknesses is to begin with a set of initial [[informant]]s that are as diverse as possible.<ref name="Morgan"/>
Efforts to improve the main disadvantage of snowball sampling resulted in the respondent-driven sampling (RDS) method.<ref>{{cite journal|last1=Heckathorn|first1=Douglas D.|title=Respondent-Driven Sampling: A New Approach to the Study of Hidden Populations|journal=Social Problems|volume=44|issue=2|pages=174–199|date=1997|url=http://www.respondentdrivensampling.org/reports/RDS1.pdf|doi=10.2307/3096941|jstor=3096941}}</ref> RDS augments the referral method by [[weighting]] the sample in order to compensate for the initial [[Randomness|non-random]] selection, which may lead to the reduction of errors occurring in sampling by the referral method.<ref name="Mirela2"/>