[dahart]

Is the graph at the bottom showing volume of sales increasing, or lack of data before 2018? I didn’t entirely understand the comments about gaps in data, what specifically is being referred to (e.g. the big dip in 2019, or the noise, or the 5x jump from 2017 to 2018?). While reading, I was wondering what the volume of sales were and if that explained price increases. If the volume really increased more than 10x, it’d be surprising if prices didn’t go up even more than they did, right? But I guess volume didn’t jump this big this fast?

It might also be nice to adjust for inflation over the last decade, which hasn’t been huge, but it makes a little difference in the price curves over time.

[aasasd]

Gaps might be due to the fact that scraping requires fiddling with the code every time the site changes even invisibly—or data just stops coming in.

[jjmccoolguy]

Can't answer conclusively. The big dip and the fall-off at the end were probably errors in my scraping. The site went down for a bit at a couple points, and the way dates were formatted changed a bit, all of which I thought I handled correctly but maybe not. And at a certain point of combing back over gaps, I just decided to be done.

I strongly get the impression that sales volumes did increase from 2014 onward, but sales in 2014, particularly in the early range there, probably appear lower than they are. IDs in that range sometimes returned normal Goodwill item pages, and sometimes returned 404-type pages. Maybe they migrated systems or something around that time?