By Ilya Grigorik on April 04, 2012 Fast and responsive services make for a great user experience. The problem is that most of us today lack the tools to reliably quantify this metric: server-side measurements do not take into account the network and the client-side latency, and most browser tools have poor visibility into the lower parts of the stack. As a result, in most cases we simply cross our
![Measuring Site Speed with Navigation Timing - igvita.com](https://cdn-ak-scissors.b.st-hatena.com/image/square/c44f451ab8b9fde2111ac7d4c79d5ba029b5b000/height=288;version=1;width=512/http%3A%2F%2Fwww.igvita.com%2Fposts%2F12%2Fperf-waterfall.png)