{"id":2044,"date":"2019-04-23T06:37:28","date_gmt":"2019-04-23T06:37:28","guid":{"rendered":"https:\/\/www.aiproblog.com\/index.php\/2019\/04\/23\/causality-the-next-most-important-thing-in-ai-ml\/"},"modified":"2019-04-23T06:37:28","modified_gmt":"2019-04-23T06:37:28","slug":"causality-the-next-most-important-thing-in-ai-ml","status":"publish","type":"post","link":"https:\/\/www.aiproblog.com\/index.php\/2019\/04\/23\/causality-the-next-most-important-thing-in-ai-ml\/","title":{"rendered":"Causality \u2013 The Next Most Important Thing in AI\/ML"},"content":{"rendered":"<p>Author: William Vorhies<\/p>\n<div>\n<p><strong><em>Summary:<\/em><\/strong><em>\u00a0 Finally there are tools that let us transcend \u2018correlation is not causation\u2019 and <strong>identify true causal factors<\/strong> and their relative strengths in our models.\u00a0 This is what prescriptive analytics was meant to be.<\/em><\/p>\n<p>\u00a0<a href=\"https:\/\/storage.ning.com\/topology\/rest\/1.0\/file\/get\/2132982369?profile=original\" target=\"_blank\" rel=\"noopener noreferrer\"><img decoding=\"async\" src=\"https:\/\/storage.ning.com\/topology\/rest\/1.0\/file\/get\/2132982369?profile=RESIZE_710x\" width=\"400\" class=\"align-center\"><\/a><\/p>\n<p>Just when I thought we\u2019d figured it all out, something comes along to make me realize I was wrong.\u00a0 And that something in AI\/ML is as simple as realizing that everything we\u2019ve done so far is just curve-fitting.\u00a0 Whether it\u2019s a scoring model or a CNN to recognize cats, it\u2019s all about association; reducing the error between the distribution of two data sets.\u00a0<\/p>\n<p>What we should have had our eye on is CAUSATION.\u00a0 How many times have you repeated \u2018correlation is not causation\u2019.\u00a0 Well it seems we didn\u2019t stop to ask how AI\/ML can actually determine causality. And now it turns out it can.<\/p>\n<p>But to achieve an understanding of causality requires us to cast loose of many of the common tools and techniques we\u2019ve been trained to apply and to understand the data from a wholly new perspective.\u00a0 Fortunately the constant advance of research and ever increasing compute capability now makes it possible for us to use new relatively friendly tools to measure causality.\u00a0<\/p>\n<p>However, make no mistake, you\u2019ll need to master the concepts of causal data analysis or you will most likely misunderstand what these tools can do.<\/p>\n<p>\u00a0<\/p>\n<p><span style=\"font-size: 12pt;\"><strong>Why Causality<\/strong><\/span><\/p>\n<p>In the age when the call for transparency in our models is a constant social media and regulatory cry, causality offers the greatest promise.\u00a0 Causal data analysis also gives you tools well beyond what you currently have to guide you to exactly what to do to get the best outcomes. \u00a0This speaks to the heart of prescriptive analytics.<\/p>\n<p>It may seem that correlation and curve fitting have done just fine at answering important questions like next best offer, is it fraud, what\u2019s the value going to be, and even is it a cat.\u00a0 But there are a whole variety of questions that our users would like to have answered like:<\/p>\n<ol>\n<li>Given that there are X factors that predict preference for a product, which ones should the business actually try to influence, and in what order of importance. (What actually causes change in the target variable)?<\/li>\n<\/ol>\n<p><em>Just ranking the strength of different variables on their ability to predict the target is not the same as selecting those that are independently predictive and evaluating their relative contribution to the outcome.<\/em><\/p>\n<ol start=\"2\">\n<li>What are the rankings of those key drivers that actually cause change and how do they compare to my competitors so that I can make smart marketing allocations.<\/li>\n<\/ol>\n<p><em>Isolating a variable like \u2018manufacturer\u2019 within the same probability model doesn\u2019t allow for re-ranking variables, and doesn\u2019t answer the causality question to begin with.<\/em><\/p>\n<ol start=\"3\">\n<li>Did that medicine actually cure the disease?<\/li>\n<\/ol>\n<p><em>This problem would require having actually performed both options on the same person, an impossibility in the real world.\u00a0 Simply splitting the sample universe into two gives a probability but not a causally supportable answer.<\/em><\/p>\n<ol start=\"4\">\n<li>Would I still have contracted cancer if I had not smoked for the last two years?<\/li>\n<\/ol>\n<p><em>Similarly, there is no way to express the probability associated with two years of not smoking without having an apriori understanding of the strength of the causal relationship not answered by our probability models.<\/em><\/p>\n<p>Some other examples of causal questions:<\/p>\n<ul>\n<li>Can the data prove whether an employer is guilty of hiring discrimination?<\/li>\n<li>What fraction of past crimes could have been avoided by a given policy?<\/li>\n<li>What was the cause of death of a given individual, in a specific incident?<\/li>\n<\/ul>\n<p>We readily understand that we can\u2019t prove causation from observations alone.\u00a0 We can observe correlation but that does not prove or even imply causation.\u00a0 There is no way we can test the statement \u201csymptoms do not cause diseases\u201d with correlation tools.\u00a0 Our models simply support that symptoms occur in the presence of disease, and disease occurs in the presence of symptoms.<\/p>\n<p>Researchers have been stuck with trying to apply \u2018common sense\u2019 directional logic outside of the mathematics, but with no way to rigorously test or prove the degree of causation.<\/p>\n<p>At a simple level, particularly in problems involving human behavior we include variables which are not mutable (age, gender, home ownership) alongside variables which might under some circumstances be controllable because they represent perceptions (is it stylish, is it reliable, is it easy, were you satisfied).<\/p>\n<p>Correlation suffices so far, but the questions answered by causality are \u2018which levers should I actually pull to effect change\u2019.\u00a0 And beyond that, \u2018what would happen if I changed some of the underlying assumptions in the model\u2019 \u2013 the ultimate scenario problem.<\/p>\n<p>\u00a0<\/p>\n<p><span style=\"font-size: 12pt;\"><strong>Techniques<\/strong><\/span><\/p>\n<p>The techniques of causal modeling, more formally known as Structural Equation Modeling (SEM) have actually been employed in the social sciences and in epidemiology for many years.\u00a0<\/p>\n<p>It\u2019s not possible to read much in this area without encountering the work of Judea Pearl, professor and renowned researcher in causality at the UCLA Computer Science Department Cognitive Systems Lab.\u00a0 His work first earned him the Turing Award in 2011 for his invention of Bayesian networks.\u00a0 Since then he has been the singular force trying to insert causality into AI\/ML.<\/p>\n<p>The techniques and mathematics of SEM are beyond the scope of summarizing in this article, but leave it to say that the fundamental math established by Pearl and the rapid evolution of graph models have made accessible causality tools available.<\/p>\n<p>There are several open source packages available including:<\/p>\n<p><a href=\"http:\/\/www.dagitty.net\/\"><strong><em><u>DAGitty<\/u><\/em><\/strong><\/a> is a browser-based environment for creating, editing, and analyzing causal models. The focus is on the use of causal diagrams for minimizing bias in empirical studies in epidemiology and other disciplines.<\/p>\n<p><a href=\"https:\/\/www.microsoft.com\/en-us\/research\/blog\/dowhy-a-library-for-causal-inference\/\"><strong><em><u>Microsoft\u2019s DoWhy<\/u><\/em><\/strong><\/a> library for causal inference.<\/p>\n<p><a href=\"http:\/\/www.phil.cmu.edu\/tetrad\/\"><strong><em><u>The Tetrad Project<\/u><\/em><\/strong><\/a> at Carnegie Mellon.<\/p>\n<p><a href=\"https:\/\/inguo.app\/\"><strong><em><u>Inguo.app<\/u><\/em><\/strong><\/a> is a commercial spinoff from NEC and backed by Dr. Pearl himself that appears to offer the most commercially ready and easily understood platform for causal analysis.\u00a0 Offered SaaS, it offers variations meant to directly facilitate explanation to users about key factors and what if scenarios.\u00a0<\/p>\n<p>Their site claims to return results in seconds where the number of variables is 60 or less, longer for more complex problems or more accurate results.\u00a0 One can easily imagine the combinatorial explosion that occurs as the number of variables increase.\u00a0<\/p>\n<p>This diagram drawn from an Inguo case study shows the relative clarity with which causal factors and their relative strength can be determined.\u00a0 In this case the streaming video client was able to rapidly focus in on the two or three controllable variables that caused increased adoption as well as the relative strength of their contributions.<\/p>\n<p>\u00a0<a href=\"https:\/\/storage.ning.com\/topology\/rest\/1.0\/file\/get\/2133006194?profile=original\" target=\"_blank\" rel=\"noopener noreferrer\"><img decoding=\"async\" src=\"https:\/\/storage.ning.com\/topology\/rest\/1.0\/file\/get\/2133006194?profile=RESIZE_710x\" width=\"450\" class=\"align-center\"><\/a><\/p>\n<p>\u00a0<\/p>\n<p><span style=\"font-size: 12pt;\"><strong>Why Understanding Causal Data Analysis is Critical<\/strong><\/span><\/p>\n<p>Although the graphics appear simple to interpret, helping your users to understand what is being predicted will require you to really understand the differences between causal data analysis and the AI\/ML we\u2019ve become used to.\u00a0 To give you just a few examples:<\/p>\n<ul>\n<li>Although we may determine that X is causal of Y it doesn\u2019t mean that X is the only cause of Y. CDA recognizes that there may be many unexamined causes of Y so the real purpose of CDA is to determine the contribution of X to the outcome Y.<\/li>\n<li>Similarly, if we add up all the contribution values of X in our model they may not come to 100%, recognizing the statistical presence of unseen variables.<\/li>\n<li>Causality isn\u2019t necessarily transitive. If we find that X causes Y and Y causes Z, we cannot conclude that X causes Z because we are dealing in \u2018average causal effects\u2019.<\/li>\n<\/ul>\n<p>For a quick look at even more facts about CDA <a href=\"https:\/\/egap.org\/methods-guides\/10-things-you-need-know-about-causal-inference\"><em><u>try this article<\/u><\/em><\/a>.<\/p>\n<p>For a deep dive into Judea Pearl\u2019s most recent summary of the field find his <a href=\"https:\/\/ftp.cs.ucla.edu\/pub\/stat_ser\/r481.pdf\"><em><u>current paper here<\/u><\/em><\/a>.<\/p>\n<p>The major takeaway here is that this is an expansion of our current toolset that finally allows us to answer user questions about what to do next based on true causal relationships.\u00a0 If you are struggling with transparency issues, examine causality tools.\u00a0 If you are simply ranking variables by the strength of correlation, you may be actively misleading users.<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p><a href=\"https:\/\/www.datasciencecentral.com\/profiles\/blog\/list?user=0h5qapp2gbuf8\"><em><u>Other articles by Bill Vorhies<\/u><\/em><\/a><\/p>\n<p>\u00a0<\/p>\n<p>About the author:\u00a0 Bill is Contributing Editor for Data Science Central.\u00a0 Bill is also President &#038; Chief Data Scientist at Data-Magnum and has practiced as a data scientist since 2001.\u00a0\u00a0\u00a0 He can be reached at:<\/p>\n<p><a href=\"mailto:Bill@DataScienceCentral.com\">Bill@DataScienceCentral.com<\/a> <span>or<\/span> <a href=\"mailto:Bill@Data-Magnum.com\">Bill@Data-Magnum.com<\/a><\/p>\n<\/div>\n<p><a href=\"https:\/\/www.datasciencecentral.com\/xn\/detail\/6448529:BlogPost:819732\">Go to Source<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Author: William Vorhies Summary:\u00a0 Finally there are tools that let us transcend \u2018correlation is not causation\u2019 and identify true causal factors and their relative strengths [&hellip;] <span class=\"read-more-link\"><a class=\"read-more\" href=\"https:\/\/www.aiproblog.com\/index.php\/2019\/04\/23\/causality-the-next-most-important-thing-in-ai-ml\/\">Read More<\/a><\/span><\/p>\n","protected":false},"author":1,"featured_media":466,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"footnotes":""},"categories":[26],"tags":[],"_links":{"self":[{"href":"https:\/\/www.aiproblog.com\/index.php\/wp-json\/wp\/v2\/posts\/2044"}],"collection":[{"href":"https:\/\/www.aiproblog.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.aiproblog.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.aiproblog.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.aiproblog.com\/index.php\/wp-json\/wp\/v2\/comments?post=2044"}],"version-history":[{"count":0,"href":"https:\/\/www.aiproblog.com\/index.php\/wp-json\/wp\/v2\/posts\/2044\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.aiproblog.com\/index.php\/wp-json\/wp\/v2\/media\/462"}],"wp:attachment":[{"href":"https:\/\/www.aiproblog.com\/index.php\/wp-json\/wp\/v2\/media?parent=2044"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.aiproblog.com\/index.php\/wp-json\/wp\/v2\/categories?post=2044"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.aiproblog.com\/index.php\/wp-json\/wp\/v2\/tags?post=2044"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}