{"id":7516,"date":"2019-04-07T16:36:00","date_gmt":"2019-04-07T14:36:00","guid":{"rendered":"https:\/\/joapen.com\/blog\/?p=7516"},"modified":"2023-04-07T18:37:48","modified_gmt":"2023-04-07T16:37:48","slug":"littles-law","status":"publish","type":"post","link":"https:\/\/joapen.com\/blog\/2019\/04\/07\/littles-law\/","title":{"rendered":"Little&#8217;s law"},"content":{"rendered":"\n<p>Little&#8217;s law is widely used in manufacturing to predict lead time based on the production rate and the amount of work-in-process, and since Kanban practitioners use it in software development is becoming more and more popular.<\/p>\n\n\n\n<p>In fact the comparison for the outsiders of a manufacturing example where things are more tangible is something that helps them a lot.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-11.png\" alt=\"\" class=\"wp-image-7518\" width=\"461\" height=\"318\" srcset=\"https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-11.png 922w, https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-11-300x207.png 300w, https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-11-768x530.png 768w\" sizes=\"auto, (max-width: 461px) 100vw, 461px\" \/><\/figure>\n<\/div>\n\n\n<h2 class=\"wp-block-heading\">The testing software scenario<\/h2>\n\n\n\n<p>I&#8217;m going to use a simple testing scenario of a software that is moved to production frequently.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Use case test<\/strong> = I will call it &#8220;test&#8221; that is composed by a set of unit tests. For instance a use case could be composed by 20 unit tests, other use cases could be composed by 50 unit tests.<\/li>\n\n\n\n<li><strong>Unit test<\/strong>: It&#8217;s the unit of work we can measure. The average time to perform it is 30 minutes. Every time a use case is requested to be sent to production it needs to pass all its unit tests.<\/li>\n\n\n\n<li><strong>Testing group capacity<\/strong> = 8 people performing 14 tests per day which means 112 tests per day.<\/li>\n<\/ul>\n\n\n\n<p>Little&#8217;s Law tells us that the average number of unit tests\u00a0<em>L<\/em>, is the effective performance rate\u00a0<em>\u03bb<\/em>, times the average time that an unit test takes to be performed\u00a0<em>W<\/em>, or simply: <strong>L = <em>\u03bb<\/em> x W<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Data table<\/h3>\n\n\n\n<p>Let&#8217;s take this data as reference<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-12-730x1024.png\" alt=\"\" class=\"wp-image-7522\" width=\"730\" height=\"1024\" srcset=\"https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-12-730x1024.png 730w, https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-12-214x300.png 214w, https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-12-768x1078.png 768w, https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-12-1094x1536.png 1094w, https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-12.png 1120w\" sizes=\"auto, (max-width: 730px) 100vw, 730px\" \/><\/figure>\n\n\n\n<p>We can see that in the beginning we have some waste of capacity:<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-13.png\" alt=\"\" class=\"wp-image-7523\" width=\"544\" height=\"308\" srcset=\"https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-13.png 725w, https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-13-300x170.png 300w\" sizes=\"auto, (max-width: 544px) 100vw, 544px\" \/><\/figure>\n<\/div>\n\n\n<p>We can see the <strong><em>\u03bb<\/em><\/strong> (lambda) clearly on the chart, provoked by the Work in progress (WIP) that already exist.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-14.png\" alt=\"\" class=\"wp-image-7524\" width=\"530\" height=\"415\" srcset=\"https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-14.png 707w, https:\/\/joapen.com\/blog\/wp-content\/uploads\/2023\/04\/image-14-300x235.png 300w\" sizes=\"auto, (max-width: 530px) 100vw, 530px\" \/><\/figure>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Little&#8217;s law is widely used in manufacturing to predict lead time based on the production rate and the amount of work-in-process, and since Kanban practitioners use it in software development is becoming more and more popular. In fact the comparison for the outsiders of a manufacturing example where things are more tangible is something that &#8230; <a title=\"Little&#8217;s law\" class=\"read-more\" href=\"https:\/\/joapen.com\/blog\/2019\/04\/07\/littles-law\/\" aria-label=\"Read more about Little&#8217;s law\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20],"tags":[],"class_list":["post-7516","post","type-post","status-publish","format-standard","hentry","category-agile-methodology"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.3 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Little&#039;s law -<\/title>\n<meta name=\"description\" content=\"Little&#039;s law is widely used in manufacturing to predict lead time based on the production rate and the amount of work-in-process, and since Kanban - joapen projects\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/joapen.com\/blog\/2019\/04\/07\/littles-law\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Little&#039;s law -\" \/>\n<meta property=\"og:description\" content=\"Little&#039;s law is widely used in manufacturing to predict lead time based on the production rate and the amount of work-in-process, and since Kanban - 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