A couple of recent blog articles on different ways to improve site performance led me to go dig up some less recent studies on the impacts of performance (or the lack thereof). I threw some of the data into some graphs. When the data is brought together it is compelling.
Greg Linden presented some Amazon.com data stating that 100 milliseconds of site delay cost 1% in loss of sales in his presentation entitled Make Data Useful.
Eric Schurman of Amazon and Jake Brutlag of Google presented the following data from bing.com. It demonstrated drops in distinct queries, query refinement, revenue per user, any clicks, and satisfaction.
Schurman and Brutlag also showed that increased site delay caused an increased user interaction delay.
They showed that Google experienced reduced site traffic even with very small site delays.
The impact of the site delays grew worse over time. After six weeks of slower performance the damage had doubled.
Even after removing the artificial delay, searches per user did not return to original levels.
A summary of a Aberdeen Group study entitled “The Performance of Web Applications: Customers are Won or Lost in One Second” claimed that Web Applications experienced similar user response from slow performance. The summary alleged that a one second increase in load time resulted in:
- 11% fewer page views
- 16% decrease in customer satisfaction
- 7% loss in conversions
Many other web performance related resources can be found at the strangeloop web performance optimization hub.