Micron Document
<!DOCTYPE html>
<html class="client-nojs vector-feature-night-mode-disabled vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-sticky-header-enabled" lang="en" dir="ltr"><head>
<meta charset="UTF-8">
<title>Nonprobability sampling</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="canonical" href="https://en.wikipedia.org/wiki/Nonprobability_sampling"> <link href="./mw/ext.cite.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.icons.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.search.codex.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/user.styles.css" rel="stylesheet" type="text/css">
<meta name="ResourceLoaderDynamicStyles" content="">
<link rel="stylesheet" type="text/css" href="./mw/site.styles.css">
<link rel="stylesheet" type="text/css" href="./mw/noscript.css">
<link rel="stylesheet" type="text/css" href="./footer.css">
<link rel="stylesheet" type="text/css" href="./vector-2022.css">
</head>
<body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Nonprobability_sampling rootpage-Nonprobability_sampling skin-vector-2022 action-view">
<div class="mw-page-container">
<div class="mw-page-container-inner">
<div class="mw-content-container">
<main id="content" class="mw-body">
<header class="mw-body-header vector-page-titlebar">
<h1 id="firstHeading" class="firstHeading mw-first-heading">
<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Nonprobability sampling</span></span>
</h1>
</header>
<a id="top"></a>
<div id="bodyContent" class="vector-body ve-init-mw-desktopArticleTarget-targetContainer" aria-labelledby="firstHeading" data-mw-ve-target-container="">
<div id="mw-content-text" class="mw-body-content mw-content-ltr" lang="en" dir="ltr"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr">
<p><b>Nonprobability sampling</b> is a form of <a href="Sampling_(statistics)" title="Sampling (statistics)">sampling</a> that does not utilise random sampling techniques where the probability of getting any particular sample may be calculated.
</p><p>Nonprobability samples are not intended to be used to infer from the sample to the general population in statistical terms. In cases where external validity is not of critical importance to the study's goals or purpose, researchers might prefer to use nonprobability sampling. Researchers may seek to use iterative nonprobability sampling for theoretical purposes, where analytical generalization is considered over statistical generalization.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup>
</p>
<meta property="mw:PageProp/toc">
<div class="mw-heading mw-heading2"><h2 id="Advantages_and_disadvantages">Advantages and disadvantages</h2></div>
<p>While probabilistic methods are suitable for large-scale studies concerned with representativeness, nonprobability approaches may be more suitable for in-depth qualitative research in which the focus is often to understand complex social phenomena.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> The in-depth analysis of a small purposive sample or case study enables the discovery and identification of patterns and causal mechanisms that do not draw time and context-free assumptions. Another advantage of nonprobability sampling is its lower cost compared to probability sampling.
</p><p>Nonprobability sampling is often not appropriate in statistical quantitative research.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading2"><h2 id="Examples">Examples</h2></div>
<p>Nonprobability sampling is widely used in qualitative research. Examples of nonprobability sampling include:
</p>
<ul><li><a href="Convenience_sampling" title="Convenience sampling">Convenience sampling</a>, where members of the population are chosen based on their relative ease of access. Such samples are biased because researchers may unconsciously approach some kinds of respondents and avoid others,<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> and respondents who volunteer for a study may differ in important ways from others.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup></li>
<li><a href="Consecutive_sampling" title="Consecutive sampling">Consecutive sampling</a>, also known as total enumerative sampling,<sup id="cite_ref-Suresh2014_7-0" class="reference"><a href="#cite_note-Suresh2014-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> is a sampling technique in which every subject meeting the criteria of inclusion is selected until the required sample size is achieved.<sup id="cite_ref-Schuster2005_8-0" class="reference"><a href="#cite_note-Schuster2005-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Bowers2011_9-0" class="reference"><a href="#cite_note-Bowers2011-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup></li>
<li><a href="Snowball_sampling" title="Snowball sampling">Snowball sampling</a>, involving the first respondent referring an acquaintance, and so on. Such samples are biased because they give people with more social connections an unknown but higher chance of selection,<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> but lead to higher response rates.</li>
<li><a href="Judgment_sample" title="Judgment sample">Judgment sampling</a> or purposive sampling, where the researcher chooses the sample based on who they think would be appropriate for the study.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> This is used primarily when there is a limited number of people that have expertise in the area being researched, or when the interest of the research is on a specific field or a small group. Types of purposive sampling include:
<ul><li>Deviant case: The researcher obtains cases that substantially differ from the dominant pattern. The case is selected in order to obtain information on unusual cases that can be specially problematic or specially good.</li>
<li>Case study: The research is limited to one group, often with a similar characteristic or of small size.</li></ul></li></ul>
<ul><li><a href="Quota_sampling" title="Quota sampling">Quota sampling</a>. This is similar to <a href="Stratified_sampling" title="Stratified sampling">stratified random sampling</a>, in which the researcher identifies subsets of the population of interest and then sets a target number for each category in the sample. Next, the researcher samples from the population of interest nonrandomly until the quotas are filled.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup></li></ul>
<p>Studies intended to use probability sampling sometimes unintentionally end up using nonprobability samples because of characteristics of the sampling method. The statistical model used can also render the data a nonprobability sample.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div>
<ul><li><a href="Sampling_(statistics)" title="Sampling (statistics)">Sampling (statistics)</a></li>
<li><a href="Cluster_sampling" title="Cluster sampling">Cluster sampling</a></li>
<li><a href="Multistage_sampling" title="Multistage sampling">Multistage sampling</a></li>
<li><a href="Simple_random_sample" title="Simple random sample">Simple random sample</a></li>
<li><a href="Systematic_sampling" title="Systematic sampling">Systematic sampling</a></li></ul>
<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
<style data-mw-deduplicate="TemplateStyles:r1239543626">
/* start https://en.wikipedia.org/ */


.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}


/* end https://en.wikipedia.org/ */
</style><div class="reflist reflist-columns references-column-width" style="column-width: 30em;">
<ol class="references">
<li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text">(Strauss and Corbin, 1990)</span>
</li>
<li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text">(Yin, 2014)</span>
</li>
<li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text">(Marshall 1996; Small 2009)</span>
</li>
<li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text">(Lucas 2014a)</span>
</li>
<li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text">(Lucas 2014a)</span>
</li>
<li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text">(Wiederman 1999)</span>
</li>
<li id="cite_note-Suresh2014-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-Suresh2014_7-0">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">
/* start https://en.wikipedia.org/ */


.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("./mw/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("./mw/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("./mw/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("./mw/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}


/* end https://en.wikipedia.org/ */
</style><cite id="CITEREFSuresh2014" class="citation book cs1">Suresh, Sharma (2014). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=9RyMBgAAQBAJ&amp;q=%22consecutive+sampling%22&amp;pg=PA224"><i>Nursing Research and Statistics</i></a>. Elsevier Health Sciences. p.&nbsp;224. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>9788131237861</bdi><span class="reference-accessdate">. Retrieved <span class="nowrap">29 September</span> 2017</span>.</cite></span>
</li>
<li id="cite_note-Schuster2005-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-Schuster2005_8-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFSchusterPowers_(MD.)2005" class="citation book cs1">Schuster, Daniel P.; Powers (MD.), William J. (2005). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=C7pZftbI0ZMC&amp;q=%22consecutive+sampling%22&amp;pg=PA46"><i>Translational and Experimental Clinical Research</i></a>. Lippincott Williams &amp; Wilkins. p.&nbsp;46. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>9780781755658</bdi><span class="reference-accessdate">. Retrieved <span class="nowrap">29 September</span> 2017</span>.</cite></span>
</li>
<li id="cite_note-Bowers2011-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-Bowers2011_9-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFBowersHouseOwens2011" class="citation book cs1">Bowers, David; House, Allan; Owens, David H. (2011). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=t729l9LE9NUC&amp;q=Consecutive+sampling&amp;pg=PT46"><i>Getting Started in Health Research</i></a>. John Wiley &amp; Sons. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>9781118292969</bdi><span class="reference-accessdate">. Retrieved <span class="nowrap">29 September</span> 2017</span>.</cite></span>
</li>
<li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text">(Berg 2006)</span>
</li>
<li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><cite id="CITEREFAhmed2024" class="citation journal cs1">Ahmed, Sirwan Khalid (December 2024). <a rel="nofollow" class="external text" href="https://linkinghub.elsevier.com/retrieve/pii/S2772906024005089">"How to choose a sampling technique and determine sample size for research: A simplified guide for researchers"</a>. <i>Oral Oncology Reports</i>. <b>12</b>: 100662. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.oor.2024.100662">10.1016/j.oor.2024.100662</a>.</cite></span>
</li>
<li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text">(Steinke, 2004)</span>
</li>
<li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text">(Lucas, 2014b)</span>
</li>
</ol></div>
<ul><li>Berg, Sven. (2006). "Snowball Sampling–I," pp.&nbsp;7817–7821 in <i>Encyclopedia of Statistical Sciences</i>, edited by Samuel Kotz, Campbell Read, N. Balakrishnan, and Brani Vidakovic. Hoboken, NJ: John Wiley and Sons, Inc.</li>
<li>Lucas, Samuel R. (2014a). <a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs11135-012-9775-3">"Beyond the Existence Proof: Ontological Conditions, Epistemological Implications, and In-Depth Interview Research."</a>, <i>Quality &amp; Quantity</i>, 48: 387–408. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs11135-012-9775-3">10.1007/s11135-012-9775-3</a>.</li>
<li>Lucas, Samuel R. (2014b). <a rel="nofollow" class="external text" href="https://link.springer.com/content/pdf/10.1007%2Fs11135-013-9865-x.pdf">"An Inconvenient Dataset: Bias and Inappropriate Inference in the Multilevel Model."</a>, <i>Quality &amp; Quantity</i>, 48: 1619–1649. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs11135-013-9865-x">10.1007/s11135-013-9865-x</a></li>
<li>Marshall, Martin N. (1996). "Sampling for Qualitative Research." <i>Family Practice</i> 13: 522–526. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Ffampra%2F13.6.522">10.1093/fampra/13.6.522</a></li>
<li>Small, Mario L. (2009). "‘How many cases do I need?’ On science and the logic of case selection in field-based research." <i>Ethnography</i> 10: 5–38. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1177%2F1466138108099586">10.1177/1466138108099586</a></li>
<li>Steinke, I. (2004). "Quality criteria in qualitative research". <i>A companion to qualitative research</i>, 184–190. London: Sage Publications</li>
<li>Strauss, A. and Corbin, J. (1990). <a rel="nofollow" class="external text" href="http://www.li.suu.edu/library/circulation/Stein/Comm%206020ksStraussCorbinBasicsQualitativeFall07.pdf">"Basics of Qualitative Research"</a>. London: Sage Publications.</li>
<li>Wiederman, Michael W. (1999). "Volunteer bias in sexuality research using college student participants." <i>Journal of Sex Research</i>, 36: 59–66, <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F00224499909551968">10.1080/00224499909551968</a>.</li>
<li>Yin, Robert K. (2014[1984]). <i>Case study research: Design and methods</i>. Thousand Oaks: Sage publications.</li></ul></div><!--htdig_noindex--><div><div class="zim-footer">
This article is issued from <a class="external text" title="Last edited on 2025-05-01" href="https://en.wikipedia.org/wiki/?title=Nonprobability_sampling&amp;oldid=1288187464">Wikipedia</a>. The text is available under <a class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">Creative Commons Attribution-Share Alike 4.0</a> unless otherwise noted. Additional terms may apply for the media files.
</div>
</div><!--/htdig_noindex--></div>
</div>
</main>
</div>
</div>
</div>

</body></html>