Yesterday, we looked at how to retrieve trend information from Terapeak’s flagship market research application, for 4 of the current Canon EOS DSLR cameras:
Our goal is to use Terapeak for eBay market data, to determine just how quickly a new camera depreciates in value.
The sample set is pulled using the keyword string "canon 650d body -kit -lens -is -grip -card -case -gift" with filters for “new” items and a category restriction of “Digital Cameras”.
Rather than using the graphical user interface (GUI) front end, we’ll take advantage of Terapeak’s Research APIs to retrieve raw data points, which we’ll further analyze in Excel.
1 31388 2013-03-11 365 1 1
Which gives us our sales statistics back in XML format:
245 1 1 1 1 1
At this point, we could write a small script to translate the XML into a CSV file for import into Excel. But because I'm only interested in 2 variables, the revenue and quantity of items sold, I can get away with a quick search and append to column command.
$ grep 'Revenue\|ItemsSold' 650data.xml | paste -d , - - >> 650d.csv
Lastly, we import the CSV files into Excel, do some cleanup of the values (deleting the extraneous XML tags), add the average price calculating (revenue / quantity) and calculate the percentage of MSRP that we see per week.
The finished data table looks like this.
Because we imported the data for the entire year, some models have many weeks with no sales activity. This is due to the cameras being released at different times during the year, which means we need to re-arrange the data so that Week 1 corresponds to the first week of sales for all the models we are comparing.
Note: Since we're normalizing the dates in this way, we lose the ability to compare the ASP to specific calendar events during the year, such as Christmas or Photokina. In practical terms, these events change the total sales (GMV) more than they do ASP, so we're safe to disregard them in this analysis.
Finally, we arrive at an apples to apples comparison of depreciation for the four camera bodies. The first observation is that, in true eBay form, there's initially a spike in ASP to levels higher than MSRP as eager buyers pay a premium to get the new cameras as soon as they are released. But beyond that, it's visually tough to tell what's going on.
Add in some trend lines though, and it's another story. This graph tells us that:
After 26 weeks, the professional 1D X and 5D Mk III hold a little less than 90% of the MSRP, with the 6D and 650D down at 70%. Key takeaways: