{"id":1517,"date":"2022-12-11T12:46:34","date_gmt":"2022-12-11T12:46:34","guid":{"rendered":"https:\/\/mondaikaiketsu.net\/?p=1517"},"modified":"2025-05-02T05:58:23","modified_gmt":"2025-05-02T05:58:23","slug":"rca2-5why","status":"publish","type":"post","link":"https:\/\/mondaikaiketsu.net\/en\/rca2-5why\/","title":{"rendered":"What is &#8220;5 Whys&#8221;?"},"content":{"rendered":"\n<p>Hello everyone. <a href=\"https:\/\/mondaikaiketsu.net\/en\/2022\/12\/10\/\u554f\u984c\u306e\u6839\u672c\u539f\u56e0\u3092\u63a2\u308b\uff5e\u305d\u306e\u2460-\u30d5\u30a3\u30c3\u30b7\u30e5\/\" target=\"_blank\" rel=\"noopener\" title=\"\">Last time<\/a>, I wrote about &#8220;Fishbone Analysis&#8221;, one of the methods used in the &#8220;Analyze&#8221; phase, which we can say is the &#8220;internal research&#8221; stage of Lean Six Sigma.<\/p>\n\n\n\n<p>This time, I would like to write about another technique used in this &#8220;Analyze&#8221; phase: the &#8220;5 whys&#8221;.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>1. What is &#8220;5 Whys&#8221;?<\/strong><\/h2>\n\n\n\n<p>The &#8220;5 Whys&#8221; originated from the origin of Lean, the Toyota Production System. It is also written in the book &#8220;Toyota Production System&#8221; by Mr. Taiichi Ohno, who is said to be the &#8220;Father of the Toyota Production System&#8221;.<\/p>\n\n\n\n<p>As the name suggests, for specific issues, we ask &#8220;Why are these issues happening&#8221;? And in the above &#8220;Toyota Production System&#8221;, it is said to repeat why five times, so it is known as &#8220;5 whys&#8221;.<\/p>\n\n\n\n<p>There is a famous example of &#8220;5 Whys&#8221;, so please watch this video (about 1 min 30 seconds).<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<div class=\"youtube\"><iframe title=\"Five Whys Jefferson Memorial Example\" src=\"https:\/\/www.youtube.com\/embed\/BEQvq99PZwo?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/div>\n<\/div><figcaption class=\"wp-element-caption\">Video1. &#8220;5 Whys&#8221; Jefferson Memorial (ASQ TV)<\/figcaption><\/figure>\n\n\n\n<p>The flow can be simplified as follows.<\/p>\n\n\n\n<p>Issue: The walls of the memorial were deteriorating.<\/p>\n\n\n\n<p>Why 1: Why the walls were deteriorating?<br>-&gt; Because they had to use high pressure cleaners every 2 weeks.<\/p>\n\n\n\n<p>Why 2: Why they had to use high pressure cleaners every 2 weeks?<br>-&gt; Because of so many bird droppings.<\/p>\n\n\n\n<p>Why 3: Why were there so many birds?<br>-&gt; Because birds were eating spiders at the memorial.<\/p>\n\n\n\n<p>Why 4: Why were there so many spiders?<br>-&gt; Because they were eating insects at the memorial.<\/p>\n\n\n\n<p>Why 5: Why were there so many insects?<br>-&gt; Insects came to the memorial when it&#8217;s lit up at night.<\/p>\n\n\n\n<p>Break down the issue like this. In this case, by taking the last factor into account, the issue was solved by turning off the light at night, and as a by-product, by turning off the light, the electricity cost was also reduced. What a beautiful case!<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>2. Key points for &#8220;5 Whys&#8221;<\/strong><\/h2>\n\n\n\n<p>I personally think that there are 2 key points in &#8220;5 Whys&#8221;.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Point 1 &#8211; Stop at a depth where you can think of realistic solutions<\/strong><\/h3>\n\n\n\n<p>It is difficult to know when to stop this deep-diving, but it is something like <strong>&#8220;every time you find a cause, discuss a solution and whether it&#8217;s realistic&#8221;<\/strong>.<\/p>\n\n\n\n<p>For example, in the above Jefferson Memorial case, if the solution to the first factor, &#8220;The condition is deteriorating due to the effects of high-pressure cleaner every two weeks&#8221;, is to &#8220;reduce the number of high-pressure cleans&#8221;, then it may slow down the deterioration of the wall. But it may also increase the damage of bird droppings and it will not be a fundamental solution, right?<\/p>\n\n\n\n<p>Conversely, too much deep-dive is also no good. For example, in the above example, in response to the 5th factor, &#8220;Insects came to the light at night&#8221;, if we further break down into &#8220;Why do insects come to the light at night?&#8221;, and if we find the answer like &#8220;because it&#8217;s a habit&#8221;, I don&#8217;t think there&#8217;s anything we can do about it. We might come up with the idea of changing behavior through genetic manipulation (laughs), but that&#8217;s not realistic.<\/p>\n\n\n\n<p>It is difficult to say for sure, but I think we have no choice but to give it a try. One thing I can say is that <strong>you don&#8217;t have to stick to &#8220;5 times&#8221;<\/strong>. It doesn&#8217;t matter how many times as long as you find a realistic solution.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Point 2 &#8211; Prudent facilitation is important<\/strong><\/h3>\n\n\n\n<p>In the Jefferson Memorial video above, the &#8220;why&#8221; is repeated and the causes are explored quite smoothly, but in reality it doesn&#8217;t work so well. In that case as well, I guess that there were various discussions along the way and that was the summarized results.<\/p>\n\n\n\n<p>It may be especially true for Japanese people that if we repeatedly ask &#8220;why?&#8221;, then it sounds like interrogation and it would be painful. So facilitation skills to prudently identify them are important (I would like to write about facilitation later in this blog).<\/p>\n\n\n\n<p>Here are some facilitation ideas;<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Idea 1 &#8211; Utilize &#8220;Silent brainstorming&#8221;<\/h4>\n\n\n\n<p>Distribute post-its to the discussion participants and ask them to write down the reasons for the question of &#8220;Why?&#8221; Once you have finished writing, you can share it and discuss which one is better. I think we can reduce the sense of &#8220;interrogation&#8221; by repeating this.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Idea 2 &#8211; Utilize &#8220;Self brainstorming&#8221;<\/h4>\n\n\n\n<p>This is a variation of Idea 1, but at first, ask each member to individually breakdown from the first issue to the root cause, then bring them together and discusses which is better.<\/p>\n\n\n\n<p>These are just a few examples, but I think it would be good if you could actually try them out and find a way that is easy for you to do.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>3. Cross-analysis of &#8220;Fishbone&#8221; and &#8220;5 whys&#8221; &#8211; but isn&#8217;t that a &#8220;Logic tree&#8221; after all? !<\/strong><\/h2>\n\n\n\n<p>It is also effective to cross-analyze (combine) this &#8220;5 Whys&#8221; and <a href=\"https:\/\/mondaikaiketsu.net\/en\/2022\/12\/10\/\u554f\u984c\u306e\u6839\u672c\u539f\u56e0\u3092\u63a2\u308b\uff5e\u305d\u306e\u2460-\u30d5\u30a3\u30c3\u30b7\u30e5\/\" target=\"_blank\" rel=\"noopener\" title=\"\">\u201cFishbone analysis\u201d<\/a> posted last time. Here is the image of cross-analysis.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"623\" src=\"https:\/\/mondaikaiketsu.net\/wp-content\/uploads\/2022\/12\/1aa9e778723edf076a4f1fc93e087815-1024x623.png\" alt=\"Cross-analysis of Fishbone and 5 Whys (Image)\" class=\"wp-image-1554\"\/><figcaption class=\"wp-element-caption\">Fig1. Cross-analysis of Fishbone and 5 Whys (Image)&nbsp;Source:&nbsp;<a href=\"https:\/\/www.robot-befriend.com\/blog\/fishbonechart\/\" target=\"_blank\" rel=\"noreferrer noopener\">ROBOT Befriend<\/a><\/figcaption><\/figure>\n\n\n\n<p>From the image of <a href=\"https:\/\/mondaikaiketsu.net\/en\/2022\/12\/10\/\u554f\u984c\u306e\u6839\u672c\u539f\u56e0\u3092\u63a2\u308b\uff5e\u305d\u306e\u2460-\u30d5\u30a3\u30c3\u30b7\u30e5\/\" target=\"_blank\" rel=\"noopener\" title=\"\">the fishbone posted last time<\/a>, the cause of &#8220;Manual is not up to date&#8221; on the bottom right is explored with &#8220;5 Whys&#8221;. By using it together like this, you can deep-dive to the appropriate depth without missing the cause of the issue.<\/p>\n\n\n\n<p>Here, if you have a good intuition, you may think, &#8220;But isn&#8217;t that a logic tree after all&#8221;? You are correct in fact.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"843\" height=\"513\" src=\"https:\/\/mondaikaiketsu.net\/wp-content\/uploads\/2022\/12\/46a4dc2a227e0f45c1593ae73b4fba86.png\" alt=\"Added 5 Whys to the logic tree (Image)\" class=\"wp-image-1553\"\/><figcaption class=\"wp-element-caption\">Fig2. Added 5 Whys to the logic tree (Image)<\/figcaption><\/figure>\n\n\n\n<p>This is also the image of the logic tree posted last time, with the elements in Fig1 above added. It&#8217;s logic tree itself, isn&#8217;t it?<\/p>\n\n\n\n<p>This point is the same conclusion as last time, but I think that there are preferences, so I think it&#8217;s good to use the one that is easy to use and fits perfectly!<\/p>\n\n\n\n<p>That\u2019s all for this time, and I would like to continue from the next time onwards. Thank you for reading until the end.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Hello everyone. Last time, I wrote about &#8220;Fishbone Analysis&#8221;, one of the methods used in the &#8220;Analyze&#8221; phase, which we can say [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":563,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_locale":"en_US","_original_post":"https:\/\/mondaikaiketsu.net\/?p=432","footnotes":""},"categories":[34,41,39],"tags":[],"class_list":["post-1517","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-as-is-en","category-analyze-en","category-internal-research-en","en-US"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/mondaikaiketsu.net\/wp-json\/wp\/v2\/posts\/1517","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mondaikaiketsu.net\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mondaikaiketsu.net\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mondaikaiketsu.net\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mondaikaiketsu.net\/wp-json\/wp\/v2\/comments?post=1517"}],"version-history":[{"count":45,"href":"https:\/\/mondaikaiketsu.net\/wp-json\/wp\/v2\/posts\/1517\/revisions"}],"predecessor-version":[{"id":3231,"href":"https:\/\/mondaikaiketsu.net\/wp-json\/wp\/v2\/posts\/1517\/revisions\/3231"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mondaikaiketsu.net\/wp-json\/wp\/v2\/media\/563"}],"wp:attachment":[{"href":"https:\/\/mondaikaiketsu.net\/wp-json\/wp\/v2\/media?parent=1517"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mondaikaiketsu.net\/wp-json\/wp\/v2\/categories?post=1517"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mondaikaiketsu.net\/wp-json\/wp\/v2\/tags?post=1517"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}