Amazon Sales Rank History and Trend
We received a suggestion today to improve our Amazon Sales Rank History feature.
The gentleman by the name of Barry suggested that we include some kind of trend feature to complement the history. This will make it easier to see how well (or badly) a product is selling at a glance.
We thought it was a great idea and implemented it. The sales trend is a moving average of the sales ranks from the last 5 days.
****** UPDATE - 14 Nov 2005******
We now present sales trends in 3 ways.
1) Best fit line based on the least square method.
2) 7-day moving average,
3) 30-day moving average. The 30 days MA may not appear unless more than 30 days of data is present.
You can see in it action here.