I maintain a Boston apartment price map, scraping Padmapper's listings to make a heatmap. Each month I run a script to update it, but last month it failed due to an API change. It had been impressively stable: I'd been running the same code unmodified for three years, with only minor modifications since a big rewrite in 2016.

The changes to get it working again this time were relatively small. When I look at the most recent results, however, I don't know whether to interpret the decline in my only post-fix data point as real:

Some possibilities:

• Prices went down (yay!)

• My scraping was wrong before but is fixed now (ok)

• My scraping was right before and is wrong now (not good!)

Looking at median prices for each size apartment, relative pricing seems pretty similar.

My best guess, looking over what's changed in the PadMapper UI, is that previously they weren't breaking out and excluding "short term" rentals, with a minimum stay of one month:

These tend to be more expensive than standard rentals, and aren't what I'm trying to track. If that is the issue then I think this probably represents fixing a bug and not a real decline.

(These charts are updates of the ones I made last time; read there for more details.)