{"id":8117,"date":"2026-07-14T01:00:42","date_gmt":"2026-07-14T07:00:42","guid":{"rendered":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/?p=8117"},"modified":"2026-06-05T11:49:46","modified_gmt":"2026-06-05T17:49:46","slug":"p-u-charts-of-xmr-charts","status":"publish","type":"post","link":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/p-u-charts-of-xmr-charts\/","title":{"rendered":"p\/u Charts or XmR Charts?"},"content":{"rendered":"\r\n<p class=\"wp-block-paragraph\">People ask: Should I use a p or u chart, or XmR chart? Which one is right? It depends&#8230;<\/p>\r\n<p><em>Download my free ebook, <a href=\"https:\/\/www.qimacros.com\/pdf\/Agile-Process-Innovation.pdf\" target=\"_blank\" rel=\"noopener\">Agile Process Innovation &#8211; Hacking Lean Six Sigma for Results<\/a>.<\/em><\/p>\r\n\r\n\r\n\r\n<p><iframe loading=\"lazy\" src=\"https:\/\/player.vimeo.com\/video\/1163313339?title=0&amp;byline=0&amp;portrait=0\" width=\"720\" height=\"405\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><span data-mce-type=\"bookmark\" style=\"display: inline-block; width: 0px; overflow: hidden; line-height: 0;\" class=\"mce_SELRES_start\">\ufeff<\/span><\/iframe><\/p>\r\n\r\n\r\n\r\n<p class=\"wp-block-paragraph\">&#8220;Hi, I&#8217;m Jay Arthur, author of \u201c<a href=\"https:\/\/www.amazon.com\/Lean-Six-Sigma-Hospitals-Improving\/dp\/1259641082\/\">Lean Six Sigma For Hospitals<\/a>\u201d and <a href=\"https:\/\/www.qimacros.com\/demo\/\">QI Macros [software]<\/a>.<\/p>\r\n<p>&#8220;One of the things I&#8217;ve noticed is I get calls from people and they ask me, &#8220;Well, Jay, should we be using a <a href=\"https:\/\/www.qimacros.com\/control-chart\/p-chart\/\">p [chart]<\/a> and <a href=\"https:\/\/www.qimacros.com\/control-chart\/u-chart\/\">u charts<\/a> or an <a href=\"https:\/\/www.qimacros.com\/control-chart\/individual-moving-range-xmr-chart\/\">XmR chart<\/a> of ratios?&#8221; And I can tell you: that depends on who your statistician leader is.<\/p>\r\n<p>&#8220;If you&#8217;re looking at the <a href=\"https:\/\/www.amazon.com\/Health-Care-Data-Guide-Improvement\/dp\/0470902582\">Healthcare Data Guide<\/a>, Lloyd Provost and his partner [Sandra Murray] love p and u charts\u2026 love them! They don&#8217;t like XmR charts. However, <a href=\"https:\/\/www.spcpress.com\/pdf\/DJW317.Jul.17.History%20of%20XmR%20Chart.pdf\">Dr. Donald Wheeler loves the XmR chart<\/a>, which he calls \u2018the Swiss Army knife of charts.\u2019<\/p>\r\n<p>&#8220;He says the reason is with p and u charts, you&#8217;re getting theoretical limits calculated based on theory of poisson and binomial and whatever. It tends to create more out-of-control points, so it gives you false alarms. He says [using] an XmR chart, we&#8217;ve just taken the numerator and the denominator and divided them and come up with a ratio. Guess what he calls that? Experiential data; that data is actually what&#8217;s really going on, and he thinks it charts better and doesn&#8217;t give you as many alerts.<\/p>\r\n<p>&#8220;Now, this is one of the things that always concerns me: there&#8217;s no one right answer, right? You know, \u2018Statistics means never having to say you&#8217;re certain\u2019 is one of the quotes I always liked, right? So we have this challenge. [John] Tukey said that the plural noun of statistician is &#8216;a quarrel of statisticians&#8217;\u2026 a quarrel, because there&#8217;s all these debates back and forth.<\/p>\r\n<p>&#8220;So what&#8217;s the right chart: a p and u chart or an XmR chart? Well, if you&#8217;re using either one, at least you&#8217;re doing that &#8211; a lot of people are just using line and bar charts. So, pick one and start using it, and I think you&#8217;ll find out a lot more about your process by using control charts than by not using control charts.<\/p>\r\n<p>&#8220;That&#8217;s my Improvement Insight. Let&#8217;s go out and improve something this week.&#8221;<\/p>\r\n","protected":false},"excerpt":{"rendered":"<p>People ask: Should I use a p or u chart, or XmR chart? Which one is right? It depends&hellip; Download my free ebook, Agile Process Innovation &ndash; Hacking Lean Six Sigma for Results. &#65279; &ldquo;Hi, I&rsquo;m Jay Arthur, author of &ldquo;Lean Six Sigma For Hospitals&rdquo; and QI Macros [software]. &ldquo;One of the things I&rsquo;ve noticed [&hellip;]<\/p>\n","protected":false},"author":4,"featured_media":8385,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[290],"tags":[439,671,168,158,170,672,226],"class_list":["post-8117","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-improvement-insights","tag-control-charts","tag-p-chart","tag-qi-macros","tag-quality-tools","tag-six-sigma","tag-u-chart","tag-xmr-chart"],"_links":{"self":[{"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/posts\/8117","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/comments?post=8117"}],"version-history":[{"count":7,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/posts\/8117\/revisions"}],"predecessor-version":[{"id":8391,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/posts\/8117\/revisions\/8391"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/media\/8385"}],"wp:attachment":[{"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/media?parent=8117"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/categories?post=8117"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/tags?post=8117"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}