{"id":673,"date":"2016-03-14T11:39:50","date_gmt":"2016-03-14T11:39:50","guid":{"rendered":"https:\/\/loadfocus.com\/blog\/?p=673"},"modified":"2016-03-11T15:40:41","modified_gmt":"2016-03-11T15:40:41","slug":"standard-deviation-and-percentiles-in-load-testing-metrics","status":"publish","type":"post","link":"https:\/\/loadfocus.com\/blog\/2016\/03\/standard-deviation-and-percentiles-in-load-testing-metrics","title":{"rendered":"Standard Deviation and Percentiles in Load Testing Metrics"},"content":{"rendered":"<\/span> < 1<\/span> minute read<\/span><\/span>

Standard deviation<\/strong> and percentiles<\/strong> are very helpful when comes to calculating the response times in a load test or a performance test.<\/p>\n

Standard deviation is just like it sounds: the routine deviation around the average. Standard Deviation can then be used as a gauge of longer response times.<\/p>\n

For normal distributions, we know that roughly 70% of the response times will be within one standard deviation of the average; and that about 95% of the responses will be within two standard deviations.<\/p>\n

The standard deviation should be a low number, if your load test is consistent in load you want to see this number low because it means most response times are close in number.<\/p>\n

If the Standard Deviation number is too low\/high you can use it to identify a potential bottleneck in your web application or website.
\nThe mean is the average, which can be pulled higher or lower by a cluster of extremely fast or slow responses being collected<\/p>\n

The Median or the 50th Percentile is great but only accounts for what 50% of your users will experience. Would be better to check the 90th(95th) percentiles values, rather than mean, to ensure only those 10% wildcard calls are ‘missed’.
\nTypically, we\u2019re only interested in the poor performers, so we pick a few top percentiles, like the 85th, 90th, 95th, and 99th.<\/p>\n

Load testing is an iterative process. Once you find one issue, you need to re-run the load test and find the next! Here are some load testing tips<\/a> on how to run your load test.<\/p>\n

LoadFocus.com<\/a> has standard deviation, mean, median (50th percentile), 90th(99th) percentiles and minimum and maximum metrics to all load tests.<\/p>\n","protected":false},"excerpt":{"rendered":"

<\/span> < 1<\/span> minute read<\/span><\/span>Standard deviation and percentiles are very helpful when comes to calculating the response times in a load test or a performance test. Standard deviation is just like it sounds: the routine deviation around the average. Standard Deviation can then be used as a gauge of longer response times. For normal distributions, we know that roughly… 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":[9,6],"tags":[109,111,110,108,112,107],"class_list":["post-673","post","type-post","status-publish","format-standard","hentry","category-load-testing","category-performance-testing","tag-90th-percentile","tag-mean","tag-median","tag-percentiles","tag-performance-metrics","tag-standard-deviation"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/posts\/673","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/comments?post=673"}],"version-history":[{"count":0,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/posts\/673\/revisions"}],"wp:attachment":[{"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/media?parent=673"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/categories?post=673"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/loadfocus.com\/blog\/wp-json\/wp\/v2\/tags?post=673"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}