Talk:Snowball sampling

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Heckathorn Articles[edit]

Somebody has added a number of references to articles by Heckathornon on "RDS". I'm a mathematician, not a sociologist, and don't know to what extent they represent state of the art in the area. However, I thought it was worth adding my two cents to the comment below, titled "Representativeness of Snowball sampling".

Despite somewhat vague claims in the prologue (and in the wikipedia article), RDS doesn't give complete protection against the bias issues inherent in snowball sampling. Instead, it makes some fairly strong model assumptions about what the underlying network/sampling process looks like, and gives some evidence that the assumptions are useful. This is great work, of course, but it is probably worth pointing out that there is no protection against the fact that a bad choice of the initial sample really can lead to bias.

Full disclosure, I commented only because the articles (and the author's website!) set off some warning lights in my head. For example, one of the mentioned article cites a well-known theorem which, translated into the language of graph sampling, says that for large enough samples, the sample is essentially independent of the starting point. He doesn't mention that, in this setting, the theorem says nothing about how big "large enough" is. Indeed, it is well-known in Markov chain theory that, without making very strong assumptions on the form of the chain, there is essentially no way of checking that a chain has run long enough until you've actually seen every state.

The articles mentioned below sound more reasonable, putting some emphasis on the fact that strong model assumptions play a very large role in trying to do any inference using snowball-based sampling. — Preceding unsigned comment added by (talk) 02:36, 5 July 2012 (UTC)

Like this one! — Preceding unsigned comment added by Williamlion (talkcontribs) 23:57, 5 December 2012 (UTC)

Representativeness of Snowball sampling[edit]

As long ago as 1990 Van Meter summarised research that showed snowball sampling can be representative if selection for the sample is treated as a stochastic process and the probability of selection for the sample is calculated.

On the other hand, Guttman showed that random samples with low response rates can be extremely unrepresentative. In many surveys the respondents are not matched back to the population and there is no way of asserting that the final responses are representative of the population being studied. (talk) 06:09, 20 December 2007 (UTC)

References van Meter K, "Methodological and Design Issues: Techniques for Assessing the Representativenees of Snowball Samples" in Lambert E (ed), The collection and Interpretation of Data from Hidden Populations, NIDA Research Monograph 98, National Institute on Drug Abuse Rockville, 31-43, 1990.

Guttman L "What is not what in Statistics. Statistical inference revisted - 1984" Bull Methodologie Sociol 4:3-35, 1984

Suggestion on how to improve the article[edit]

The content of the article is not well-organized, and most of them are redundant. To make the article more neat and well-organized, we would like to rearrange some of the parts. Divided the usage of snowball sampling part into small pieces which seems easier to read. In addition, delete the redundant content and complete the article to make it more integrated. We specify the advantage and disadvantage of snowball sampling. And since the article mentioned disadvantage, we think it is better to indicate the method to improve the snowball sampling.

Secondly, the article is lack of references and examples which make it less reliable. As a result, we searched some paperes relative to the article and added them as the references. — Preceding unsigned comment added by LeiLei63 (talkcontribs) 00:31, 18 October 2012 (UTC)

Good suggestion[edit]

The suggestion is very constructive and promising. It can improve the organize the article. — Preceding unsigned comment added by KatePolice (talkcontribs) 00:01, 6 December 2012 (UTC)

Pictures or diagrams?[edit]

Hi there, as a random page patroller I came across this page and found it hard to read because there are no pictures or diagrams. Just thought somebody might have a nice picture in mind. Thanks - I hope this suggestion is useful. Creeper jack1 (talk) 20:41, 8 February 2013 (UTC)

Computer Science references[edit]

The computer science references seem out of place to me. This isn't a computer science article and the analogies to BFS will probably confuse readers that aren't already familiar with the concept. I suggest creating a "relationship to BFS" subsection for this material rather than putting it in the introduction. — Preceding unsigned comment added by (talk) 07:12, 8 April 2014 (UTC)

=======Discussion Board for group Pratibha VS, Bdarren, CAP129 and WenZhang61=====[edit]

We divided the work on improving article as follows

Pratibha VS - Improvements to Definition section and overall faults, if any, Cleaning up reference link, Bdarren - "Improvements for snowball sampling" CAP129 - Improvements to "Example" section WenZhang61 - Improvements to "Application of snowball sampling". Pratibha VS (talk) — Preceding undated comment added 00:55, 3 December 2014 (UTC)

Suggestions on Improving the article[edit]

Two main aspects need to be improved.

1. The article is obviously lack references and some of the external links is link to an empty page. Furthermore there are nearly no internal links for us to refer to. Update those links would be necessary.

2. A term called Peer Esteem Snowballing should be added to the Improvements for snowball sampling section. In this article Dr Dimitrios C Christopoulos mentioned that snowball sampling is not a robust measure of reliability when applied to the public, but if we want to investigate small populations of expert opinion, a sampling method like this is perfect for the study. This is a pretty refreshing idea because the reliability of snowball sampling is depend on the study it being used.

Bdarren (talk) 18:24, 7 November 2014 (UTC)

Peer Esteem Snowballing[edit]

This section originally read like it was copied and pasted from a paper, so I updated the style. However it doesn't actually describe what Peer Esteem Snowballing is or how it differs from traditional snowball sampling. Jenlouised (talk) 21:59, 28 April 2017 (UTC)

Suggestion on definition/main topic and References[edit]

1. The main definition can include some more details like. For eg: under Nonprobability sampling, "Snowball sampling" can be best example of Purposive Sampling or Judgmental sampling. The definition can be improved with respect to some other aspects.

2. An important concept/advantage of Snowball sampling as how do we reach hard to reach population through this study can give better visualization to this article by referring to article "Faugier, J., & Sargeant M. (1997). Sampling hard to reach populations. Journal of Advanced Nursing, 26, 790-797."

3. Same references are mentioned multiple times eg: David L., Morgan (2008). The SAGE Encyclopedia of Qualitative Research Methods. SAGE Publications, Inc. pp. 816–817. ISBN 9781412941631

4. As one of my teammates Bdarren said some of the external links are broken. I have fixed all the external links.

5. Statistical inferences are missing from the article. An important source for this would be "Kalton and Anderson (1986)" It also discusses compares different sampling procedures and their limitations, which is good comparison to other techniques.

6. There is no reference from where the Method is taken

7. Added important missing advantages and disadvantages eg: Low cost, Lack of control over the sampling method — Preceding unsigned comment added by Pratibha VS (talkcontribs) 23:40, 3 December 2014 (UTC)

Pratibha VS (talk) 06:15, 8 November 2014 (UTC)

Suggestions on changes to the 'Examples' part[edit]

1. The examples given in this section are redundant and confusing. They are just some general ideas seemingly made up by the author for the lack of reliable references and in-detial explanations. This section is supposed to give an concrete experiment that has been done to illustrate the method. For example, the research about heroin-using populations (Kaplan C D, Korf D, Sterk C. Temporal and social contexts of heroin-using populations an illustration of the snowball sampling technique[J]. The Journal of nervous and mental disease, 1987, 175(9): 566-574.) can be cited and illustrated as a good example. The method, research steps, results and analysis should be included so that the readers can understand how snowball sampling is applied in practice.

2. Wrong citation. As the only reference in this section, Browne, Kath's research on non‐heterosexual women is however not mentioned in the passages at all. It is referred in the "Improvements for snowball sampling" section, but the citation of reference 15 is wrong, too. To improve, if the contents stay unchanged, the references concerned should at least be included. Like the research about heroin-using populations (Kaplan C D, Korf D, Sterk C. Temporal and social contexts of heroin-using populations an illustration of the snowball sampling technique[J]. The Journal of nervous and mental disease, 1987, 175(9): 566-574.)

3. With regard to the contents, it may be inappropriate to divide this section into "positive" and "negative" subsections. Examples should be illustrated in a neutral tone, with the research background, candidates information, processes, figures, models and statistics etc. to make it more academic and helpful. And the positive and negative outcomes should be mentioned in the "advantages" and "disadvantages" parts.

CAP129 (talk) 23:37, 10 November 2014 (UTC)

Suggestions on "Applications" part[edit]

WenZhang61 (talk) 07:09, 12 November 2014 (UTC)

First of all, I agree with Bdarren's views--"this article obviously lacks references and nearly no internal links". Especially in "Applications of snowball sampling" part, only one same reference and no internal link are included.
In addition, I have some similar viewpoints with CAP129. This article partly mixes up the "applications" and "examples" parts. The "Application" part makes a great effort to explain an example of 3M. The "Example" part can only be perceived as a further literal explanations to the advantages and disadvantages without some detail statistics or cases.

To sum up, "Application" part can be improved in following ways:

  1. This part should include some internal or external links to make it more readable and convincing. For example, some words should have internal or external links in this article.(e.g. 3M, veterinarian, social network)
  2. The content need to be reconstructed. Compared with the "Examples" part, the "Applications" part should focus on the fields that snowball sampling can be applied in. For instance, snowball sampling can be used as an evaluation method in social network field, or a tool for gathering information in expert field such as surgery, etc. Additionally, the advantages and disadvantages should disengage from the "Application" part to set up an independent part.
  3. Neutral. In the "advantages and disadvantages" part, this article should state it neutrally. Now, it pays more attention to the disadvantages. Moreover, some defenses against those disadvantages or solutions to inevitable problems should be mentioned.

Wrong citation in the "Improvements for snowball sampling"[edit]

CAP129 (talk) 22:54, 3 December 2014 (UTC) To Bdarren: I saw you edited this section and made good improvement, but there is one mistake that you didn't notice. The reference 15 in the first paragraph is wrong. It should refer to reference 13 or 14 (obviously they are the same, so maybe you should delete one of them).

About Wrong Citation[edit]

To CAP129: Yes, you are right. I've already mapped it to the right reference. Thanks!

Bdarren (talk) 23:21, 3 December 2014 (UTC)

Plans to add distinction between virtual and traditional snowball sampling[edit]

Virtual snowball sampling (sampling which uses virtual networks) deserves more attention than the article currently devotes to this topic, due to additional examples, advantages and disadvantages that it brings in addition to the traditional snowball sampling. Based on the article Baltar, F., & Brunet, I. (2012). Social research 2.0: virtual snowball sampling method using Facebook. Internet Research, 22(1), 57-74., I will change current “Snowball sampling” article by:

1. Adding the distinction between traditional and virtual sampling in snowball sampling definition.

2. In the new section I will compare traditional and online snowball sampling by providing additional advantages and disadvantages unique for online sampling i.e. problems with access to the Internet, sample selection bias based on characteristics of online population, expansion of geographical scope of the sample, sample size increase in comparison with traditional snowball sampling. I think it will also be a good idea to combine all advantages and disadvantages in one table and check which appear in online and which in traditional sampling.

3. I will also provide the example of use of snowball sampling in online research of Argentinean immigrant entrepreneurs in Spain which uses data obtained from Facebook and I will add it to the section “Social computing” (application field). I think that by providing this example I will be able to show that snowball sampling could have applications in research concerning not only people with some sort of health problems or criminals (which is the impression that one can get from reading the current article).

PaulinKa (talk) 18:34, 24 February 2017 (UTC)

All sounds very good PaulinKa Rostaf (talk) 14:50, 28 February 2017 (UTC)

Good suggestion: distinction between virtual and traditional snowball sampling[edit]

I support the suggested edits. The advantage / disadvantage section needs to be elaborated more and good idea to show them in tabular format. In addition, by providing distinction between virtual and traditional snowball sampling, it will allow reader to understand the broader implication of this method. Waqas Amin (talk) 03:40, 26 February 2017 (UTC)

Suggestions to add Snowball Sampling Method (SSM) use in Conflict Environment and Marginalized Population:[edit]

I am suggesting to contribute the use of Snowball Sampling Method (SSM) in the conflict environment and marginalized puplolation where it is challenging to reach potential interviewees. The current article needs to emphasize more on this topic, because use of SSM has shown great degree of success in conducting research in conflict environment and marginalized puplolation as per many research studies. Based on “Field research in conflict environments: Methodological challenges and snowball sampling” article by Nissim Cohen and Tamar Arieli in 2011, I would suggest following changes in the article that will improve the quality of this article by providing more insight on the methodology advantages/disadvantages, ethical issues, statistical approach and SSM applications.

1- I will describe the critical challenges of conducting research in conflict environment and how the use of SSM has overcome these challenges. The major issue is distrust of conflict environment population to participate in research studies. 2- In the methodology section, I would suggest to add some details about the use of SSM in qualitative and quantitative research where finding potential interviewees from a population with specific characteristics that is only identifiable by the population individuals like formal and informal means of reaching a target group and SSM use when preferred methodologies are not possible to implement (using quota sampling). 3- In the advantages/disadvantages section, I would explain more about the advantages like locating, accessing, involving and disadvantages like limitation. The representatively is the main limitation of SSM and it mostly caused by the “Gatekeepers”, the facilitator between researcher and potential respondent and willingness to participate. This can be overcome in SSM by initiating parallel snowball and quota samplings. 4- I would also suggest to add some examples about the use of SSM in conflict environment and marginalized population in the SSM application section like “The value of SSM use in the context of the Israel and Arab Conflict”. --Waqas Amin (talk) 17:51, 25 February 2017 (UTC)

These changes all sound great, Waqas Amin. Just pay attention that the article currently has lots of headings with little information in each section or subsection. It will be beneficial to make sure your changes will help to improve the structure of the paper as well. 14:53, 28 February 2017 (UTC) — Preceding unsigned comment added by Rostaf (talkcontribs)

Comments about Suggestions to add Snowball Sampling Method (SSM) use in Conflict Environment and Marginalized Population[edit]

To Waqas Amin: I think that your suggestions will improve the quality of the article. It certainly needs more examples and insight into methodology part (and good references for his part). I only have a few comments. You mention that “use of SSM has shown great degree of success in conducting research in conflict environment and marginalized population”. The reason why we are able to see so many examples of use of snowball sampling in conflict and marginalized population is because there has been an extensive research done in this field. I’m not exactly sure how you want to structure the article but make sure that the reader will not get the impression that it is not successful in other fields unless you are able to provide the reference. Also, I have noticed that you use the SSN acronym for Snowball Sampling Method – the article never uses it, it refers to the method simply as “Snowball Sampling”. So you either need to follow what the article already has or (in order to be consistent) introduce it at the beginning of the definition. PaulinKa (talk) 17:51, 27 February 2017 (UTC)

PaulinKa, to respond to others on talkpages, you can create a thread by indenting your response like I have done here Rostaf (talk) 14:41, 28 February 2017 (UTC)
That's much better, thank you Rstaf! PaulinKa (talk) 17:49, 28 February 2017 (UTC)

Copy and paste material?[edit]

The last 3 sections read as if they've been copied and pasted from a paper on this topic. I'm adding a style template, suggesting they be rewritten in encyclopedic tone. — Preceding unsigned comment added by Jenlouised (talkcontribs) 21:34, 28 April 2017 (UTC)

Statistics on snowball statistics - not relevant[edit]

I have temporarily deleted the following section, as it appears to contain no relevance to Snowball sampling. All of the studies listed are large, mailout surveys. These don't have any relation to snowball sampling.

Statistics on Snowball sampling
In U.K. where the telephone coverage is not as high as in USA, Harris(1971) conducted survey of handicapped and impaired. He screened 250,000 households, by mail questionnaires at the initial phase; a response rate of 85.6 percent was obtained. CartWright(1964) sent a mail questionnaires to 29400 persons to identify those who had been in hospitals in the last six months, and obtained a response rate of 87 percent. Hunt(1978) sent a screening questionnaires seeking basic demographic details about the members of 11500 households to identify a sample of elderly, and achieved a response rate of 8O percent. Although these response rates are high there is high risk that non-respondents include a larger proportion of members of the rare population.

The reference for this paragraph is as follows. If desired, someone could re-read the reference, identify how this information is related to SNowball sampling, and then revise the above paragraph and re-insert it.

Kalton, G., & Anderson, D. W. (1986). Sampling rare populations. Journal of the royal statistical society. Series A (general), 65-82. sampling

Jenlouised (talk) 22:05, 28 April 2017 (UTC)