Past Meetup

The Statistics of Web Performance Analysis with Philip Tellis

This Meetup is past

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Wayfair Offices - 4 Copley Place

4 Copley Place Floor 7 · Boston, MA

How to find us

Come up to the 24th floor, call 802-522-6294 with any problems

Location image of event venue


If you're interested in measuring real user web performance, you'll find tools like boomerang or episodes quite handy. Some popular web frameworks even have modules that make it easy to add them to your site. However, what does one do once one has collected the data? How do you filter out the noise and get meaningful insights from the data?

In this talk, I'll go over the techniques we've picked up by analyzing millions of datapoints daily. I'll cover some simple rules to filter out invalid data, and the statistics to analyze and make sense of what's left. Do you use the mean, median or mode? What about the geometric mean and standard deviation? How confident are we in the results? And finally, why should we care?

This talk should help you gain useful insights from a histogram, or at the very least point you in the right direction for further analysis.

Philip Tellis is the co-founder and CTO of LogNormal, where he works to measure real user performance characteristics for everyone else. Prior to starting LogNormal, Philip worked with Yahoo!'s performance and security teams where he built the boomerang JavaScript library (among other things).

When he's not hacking on something, Philip spends his time cooking, reading, biking and kayaking down the Charles with his wife.


Street View:


6:30-7:15 Eat pizza and meet other members
7:15-8:15 Presentation
8:15-9:00 Q&A, general socializing and more pizza eating