Here’s an article from Google Webmaster Central Blog written by Mushan Yang (杨沐杉) and Xiangyu Luo (罗翔宇) which I thought you might find of interest.

“PageSpeed Insights provides information about how well a page adheres to a set of best practices. In the past, these recommendations were presented without the context of how fast the page performed in the real world, which made it hard to understand when it was appropriate to apply these optimizations. ”

To read more head over to Google Webmaster Central Blog

Till next time,
D