How Are Traffic Trend Graphs Calculated?
The Trend graph shows you a three-day moving average of the site’s daily traffic rank, charted over time. The daily traffic rank reflects the traffic to the site based on data for a single day. In contrast, the main traffic rank shown in the Alexa Toolbar and elsewhere in the service is calculated from three months of aggregate traffic data. Daily traffic rankings will sometimes benefit sites with sporadically high traffic, while the three-month traffic ranking benefits sites with consistent traffic over time. Since we feel that consistent traffic is a better indication of a site’s value, we’ve chosen to use the three-month traffic rank to represent the site’s overall popularity. We use the daily traffic rank in the Trend graphs because it allows you to see short-term fluctuations in traffic much more clearly. It is possible for a site’s three-month traffic rank to be higher than any single daily rank shown in the Trend graph. On any given day there may be many sites that temporarily s
