Patterns data issue

Hi Safegraph,
I use all *-safegraph_np_home_panel_0.csv files to calculate the sum of number_devices_residing and number_devices_primary_daytime for each month. And I display the trend line below:

There is a peak between Jan 22 and Aug 22 then a significant drop at Aug 22.
Also, I aggregated *-safegraph_np_patterns_0_0.csv.gz over destTract (OrgTract) x Month. I found the same issue for number_devices_primary_daytime (nDev_day) column.

Can you explain the reason behind? Thank you for the help!


Hi @yunjieh, thanks for reporting this. I’ve reported this to the SafeGraph team to see if we can get a little more information. I’ll update my response if I find out more.

From what I initially understand, there was a change in the supplier data that impacted August because of a significant increase in home visits with no meaningful increase in POI visits. This disrupted the normalization scaling.

As mentioned in another post, we’re actually beginning the transition to another Patterns supplier in Jan 2023. The visitation counts of this new provider will be more consistent year-over-year so you should encounter fewer of these issues. More to come:

Here’s a Google Collab notebook the SafeGraph team created to address this issue: Google Colab