The Rational Tester loves performance testing tips and tidbits. One such gem came across the desk today, thanks to Marissa Mayer of Google. At the Web 2.0 conference Marissa explained how Google was doing some experiments on the number of search results users wanted returned for any given query. Survey results from the users indicated that more is preferred to less – so in the lab they upped the search results returned from 10 to 30. The result? A 20% decline in search traffic.
To make a long story short, this counter-intuitive result was due to a performance issue. Upon analysis, the Google team discovered that the cost of increasing the results from 10 to 30 was .5 seconds. 10 Results takes .4 seconds to present, 30 results takes .9. So one half of one second cause a 20% decline in usage, which leads to a direct decline in search related revenue.
So the next time you’re looking at system performance, don’t be so quick to dismiss (what you might otherwise consider) a small difference in response time. Apparently, every second counts.