{"id":59673,"date":"2022-02-08T13:46:00","date_gmt":"2022-02-08T17:46:00","guid":{"rendered":"https:\/\/www.shortform.com\/blog\/?p=59673"},"modified":"2022-02-15T09:08:56","modified_gmt":"2022-02-15T13:08:56","slug":"sample-selection-bias","status":"publish","type":"post","link":"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/","title":{"rendered":"The Dangers of the Sample Selection Bias"},"content":{"rendered":"\n<p>What is self-selection bias? How does self-selection bias influence research findings? <\/p>\n\n\n\n<p>Sample <a href=\"https:\/\/www.shortform.com\/blog\/selection-bias-in-research\/\">selection bias<\/a> is a common issue in psychological studies that involve statistical analysis. Specifically, people only join studies they\u2019re comfortable responding to, which alters your data. Those who might provide embarrassing or somehow \u201cundesirable\u201d responses simply won\u2019t take part, narrowing your study\u2019s scope and skewing the results.&nbsp;<\/p>\n\n\n\n<p>Here&#8217;s how sample selection bias skews research results and how to work around it. <\/p>\n\n\n\n<!--more-->\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-self-selection-bias\"><strong>Self-Selection Bias<\/strong><\/h2>\n\n\n\n<p>In statistics, self-selection or sample selection bias is where participants in a research study self-select themselves by choosing to participate, creating a biased sample.<\/p>\n\n\n\n<p>Say, for example, a school does a survey on alcohol and drug use. Only students who are comfortable discussing their usage will respond. Students who use alcohol and drugs more are less likely to participate either out of fear of penalization or because they\u2019re ashamed of their usage. This means your results will skew toward lower alcohol and drug usage and not reflect the true usage at the school.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-working-around-self-selection-bias\"><strong>Working Around Self-Selection Bias<\/strong><\/h3>\n\n\n\n<p>How can you avoid self-selection bias? Dobelli doesn\u2019t say, but others say <a href=\"https:\/\/www.statisticshowto.com\/self-selection-bias\/\">the only way to completely eliminate self-selection bias is studying people who don\u2019t know they\u2019re being studied<\/a>. However, uninformed research is unethical. Both the U.S. <a href=\"https:\/\/www.fda.gov\/patients\/clinical-trials-what-patients-need-know\/informed-consent-clinical-trials\">Food and Drug Administration<\/a> and the <a href=\"https:\/\/www.apa.org\/ethics\/code\/index?item=11#:~:text=3.10%20Informed%20Consent-,(a)%20When%20psychologists%20conduct%20research%20or%20provide%20assessment%2C%20therapy%2C%20counseling,Informed%20Consent%20in%20Assessments%20%3B%20and%2010.01%2C%20Informed%20Consent%20to%20Therapy%20.),-3.11%20Psychological%20Services\">American Psychological Association<\/a> require researchers to receive informed consent from all study participants.<\/p>\n\n\n\n<p>However, you can <em>limit <\/em>self-selection bias. Most studies do this by collecting demographic information: Researchers look for patterns in the demographics of people who chose to participate, and <a href=\"https:\/\/www.statisticshowto.com\/weighting-factor\/\">alter how they weigh the responses<\/a> to reduce self-selection bias. Specifically, they <a href=\"https:\/\/www.statisticshowto.com\/self-selection-bias\/\">give greater weight to results from those less likely to self-select, and lesser weight to results from those likely to self-select<\/a>.&nbsp;<\/p>\n\n\n\n<p>Returning to our earlier example, if you notice that many A- and B-students respond to your survey, reporting low drug and alcohol use, but only a few C- and D-students respond, reporting higher drug and alcohol use, you might weigh those C- and D-student responses more heavily than the A- and B-student responses. The C- and D-students would be less likely to self-select and participate in the study due to shame around their grades and substance use. Weighing the responses of those that <em>do<\/em> respond more highly will counteract the impact of this lack of self-selection.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>What is self-selection bias? How does self-selection bias influence research findings? Sample selection bias is a common issue in psychological studies that involve statistical analysis. Specifically, people only join studies they\u2019re comfortable responding to, which alters your data. Those who might provide embarrassing or somehow \u201cundesirable\u201d responses simply won\u2019t take part, narrowing your study\u2019s scope and skewing the results.&nbsp; Here&#8217;s how sample selection bias skews research results and how to work around it.<\/p>\n","protected":false},"author":7,"featured_media":13359,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[9,160,25],"tags":[576],"class_list":["post-59673","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-psychology","category-science","category-statistics","tag-the-art-of-thinking-clearly","","tg-column-two"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v24.3 (Yoast SEO v24.3) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>The Dangers of the Sample Selection Bias - Shortform Books<\/title>\n<meta name=\"description\" content=\"Sample selection bias is a common statistical error in which the nature of the participants in a study influences its outcome. Learn more.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The Dangers of the Sample Selection Bias\" \/>\n<meta property=\"og:description\" content=\"Sample selection bias is a common statistical error in which the nature of the participants in a study influences its outcome. Learn more.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/\" \/>\n<meta property=\"og:site_name\" content=\"Shortform Books\" \/>\n<meta property=\"article:published_time\" content=\"2022-02-08T17:46:00+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2022-02-15T13:08:56+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/s3.amazonaws.com\/wordpress.shortform.com\/blog\/wp-content\/uploads\/2020\/08\/okrs-measure-what-matters-scaled.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"2560\" \/>\n\t<meta property=\"og:image:height\" content=\"1695\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"Darya Sinusoid\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Darya Sinusoid\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/\"},\"author\":{\"name\":\"Darya Sinusoid\",\"@id\":\"https:\/\/www.shortform.com\/blog\/#\/schema\/person\/0421cce75bc249b11e2517b3a91f9c46\"},\"headline\":\"The Dangers of the Sample Selection Bias\",\"datePublished\":\"2022-02-08T17:46:00+00:00\",\"dateModified\":\"2022-02-15T13:08:56+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/\"},\"wordCount\":403,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\/\/www.shortform.com\/blog\/#organization\"},\"image\":{\"@id\":\"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/www.shortform.com\/blog\/wp-content\/uploads\/2020\/08\/okrs-measure-what-matters-scaled.jpg\",\"keywords\":[\"The Art of Thinking Clearly\"],\"articleSection\":[\"Psychology\",\"Science\",\"Statistics\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/\",\"url\":\"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/\",\"name\":\"The Dangers of the Sample Selection Bias - Shortform Books\",\"isPartOf\":{\"@id\":\"https:\/\/www.shortform.com\/blog\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/www.shortform.com\/blog\/sample-selection-bias\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/www.shortform.com\/blog\/wp-content\/uploads\/2020\/08\/okrs-measure-what-matters-scaled.jpg\",\"datePublished\":\"2022-02-08T17:46:00+00:00\",\"dateModified\":\"2022-02-15T13:08:56+00:00\",\"description\":\"Sample selection bias is a common statistical error in which the nature of the participants in a study influences its outcome. 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