UX Metrics for the Modern Web
Synthetic Measurement Tools
RUM tools are excellent for measuring performance, but sometimes we really need synthetic measurements—especially for evaluating performance of pre-production environments (code/stack). Synthetic tools pre-date RUM and are more mature from a software development standpoint.
A few of the big ones include WebPageTest, CatchPoint and Keynote Systems. Synthetic tools can very quickly give you an objective view of site performance. The key is to make sure that you understand the limitations of these tools. Synthetic measurements operating in controlled environments cannot approximate live user experiences—particularly not for highly dynamic applications. That said, synthetics are excellent tools for benchmarking performance, because they provide a more consistent point of comparison. So if you are tuning a website or application, then synthetics can be a great way to nail down the efficacy of your Web performance optimization tweaks.
So now you have an overview of some of the key Web performance terms and their relevance to the new dynamic application landscape and can better understand the geekspeak emanating from your Web performance team.