Fun With Numbers: Amazon Rank Progression for US Releases (March 4)

In the interest of not posting all the tank data in a horrible confuse-a-gram like the one for the February data, I’ll be posting the 1 week before-and-after amazon rank results for the March data after I’m done collecting it. Additionally, I’ll be posting updates on an interesting finding I’ve had with the data for a particular series that will likely help me nail down the  worth of the lower (100,000th or worse in movies and TV) ranking numbers.

How will I do that? Aria the Natural’s part 2 release was low-stocked and has not been purchased frequently. That means that, each day, the amazon page displays the total number of disks in stock at that time. This means I can use the daily decline (or lack thereof) in daily stock to determine how much its approximate ranking is worth in terms of daily sales. Emphasis on “lack thereof”:

Aria-InstockChart is date, rank, # in stock

This is a strong indication that places worse than 120,000th correspond to 1 or fewer purchases per day, which is an extremely useful bit of information. Whatever the eventual shape of any amazon-rank-to-sales fit ends up being, it should probably approach zero for rank values of that size. Also, it makes a handy cutoff point for measuring sales longevity; # of days above 120,000th place can be used to compare with series release-period sales peak as an important alternative measure of success. Selling 3 copies over 100 days is better than selling 10 copies in 1 day and 0-1 in every other.

Graphs of each of the eleven March 4th releases tracked over the past 2 weeks are shown after the break. I’ll save commentary for the end of the month, when I have at least the complete sample to work with, and at best a reasonable fit for the ballpark each series’ ranking is in in terms of total sales.

AriaNatural_p2 Casshan_BD Casshan_DVD Cobra GalaxyRailways_SAVE MariaHolic_BD MariaHolic_DVD MyselfYourself Nadia_BD Nadia_DVD OnePiece_s5v6


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