{"id":3064,"date":"2010-04-05T16:16:56","date_gmt":"2010-04-05T23:16:56","guid":{"rendered":"http:\/\/blog.mozilla.org\/metrics\/?p=3064"},"modified":"2019-09-18T12:05:36","modified_gmt":"2019-09-18T19:05:36","slug":"firefox-page-load-speed-part-ii","status":"publish","type":"post","link":"https:\/\/blog.mozilla.org\/metrics\/2010\/04\/05\/firefox-page-load-speed-part-ii\/","title":{"rendered":"Firefox & Page Load Speed \u2013 Part II"},"content":{"rendered":"

Let’s start with the punchline: By making a few minor tweaks to our top landing pages, we can drive an additional 60,000,000<\/em> Firefox downloads per year.<\/p>\n

60 million is a big number, so let’s add a little context. Looking back at our record breaking download day<\/a> during the launch of Fx3 (June 2008), a total of 8,002,530 people downloaded Firefox. Adding 60 million downloads is akin to running 10 Download Day campaigns per year.<\/p>\n

What are the tweaks?<\/p>\n

It comes down just one factor — speed. As it stands, our landing pages can be painfully slow. Take a look:<\/p>\n

<\/embed><\/object><\/p>\n

The entire Chrome landing page loads before our header appears. Worse yet, our download button doesn’t appear for 7 seconds! While this video does not reflect the experience of every IE.html visitor, nearly a quarter of our visitors wait at least this long.<\/p>\n

Now that we know this page is slow, let’s make it faster. To do so, I thought back to the 2 weeks I shopped a class on high performance web sites. But, I couldn’t remember much, so I asked Ryan Doherty<\/a> for some tips. He had two simple suggestions: combine (or remove) the JavaScript files and inline the CSS.<\/p>\n

Results<\/strong>
\nAfter implementing these changes in an A\/B test, we saw impressive results. Previously<\/a>, we predicted a 1 second reduction in page load speed would improve download conversions by 2.7%. In reality, our optimized experimental variation shaved 2.2 seconds off the average page load time and increased download conversions by 15.4%!<\/p>\n

With 275,000 daily visitors, a 15% improvement on this single English page translates to 10.28 million additional downloads per year. And, if we’re able to achieve a similar performance boost across our<\/a> other<\/a> top<\/a> landing<\/a> pages, we’ll drive in excess of 60 million yearly Firefox downloads.<\/p>\n

Yeah, but…<\/strong>
\n15% looks great, but how confident are we?<\/p>\n

Running a one-sided Student’s t-test with a means difference of 14%, our experimental data yields a P value of 0.000051. This means that there is only a 0.0051% chance that we would obtain a 14% (or greater) improvement if the real effect wasn’t at least this large.<\/p>\n

\"\"<\/a><\/p>\n

Next Steps<\/strong>
\nWe’re excited by our initial results, but are only just getting started. We have a bunch more optimizations<\/a> to try and have some ideas of our own. For example, we want to test a landing page that loads the download button before all other page elements. Later on, we plan to test more elements of Firefox’s adoption funnel<\/a>, including the download and First Run experiences.<\/p>\n

Many thanks go out to Ryan, Fred, Laura, and Matthew<\/a>, who suggested running performance tests and has already made impressive performance improvements on addons.mozilla.org<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Let’s start with the punchline: By making a few minor tweaks to our top landing pages, we can drive an additional 60,000,000 Firefox downloads per year. 60 million is a big number, so let’s add a little context. Looking back … Continue reading<\/a><\/p>\n","protected":false},"author":1557,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[855,827],"tags":[],"_links":{"self":[{"href":"https:\/\/blog.mozilla.org\/metrics\/wp-json\/wp\/v2\/posts\/3064"}],"collection":[{"href":"https:\/\/blog.mozilla.org\/metrics\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.mozilla.org\/metrics\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.mozilla.org\/metrics\/wp-json\/wp\/v2\/users\/1557"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.mozilla.org\/metrics\/wp-json\/wp\/v2\/comments?post=3064"}],"version-history":[{"count":0,"href":"https:\/\/blog.mozilla.org\/metrics\/wp-json\/wp\/v2\/posts\/3064\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.mozilla.org\/metrics\/wp-json\/wp\/v2\/media?parent=3064"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.mozilla.org\/metrics\/wp-json\/wp\/v2\/categories?post=3064"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.mozilla.org\/metrics\/wp-json\/wp\/v2\/tags?post=3064"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}