IP-to-Geolocation Mapping Impact to 'US DMA' Dimension

[JoshSt]

Per 2022 release notes (https://experienceleague.adobe.com/docs/analytics/release-notes/previous/2022.html?lang=en), an update/upgrade was made to the IP-to-geolocation mapping as called out below.  Around this time of the update, we saw a disproportioned shift in DMA traffic, particularly increases (2x the historical trend) in the NYC/Chicago areas. Is this expected and/or the result of the update/upgrade to IP mapping?  Is there any additional documentation as to what changed with the update/upgrade? 

"Our vendor for IP lookups, Digital Element, is upgrading to a new improved dataset (NetAcuity Pulse) for IP-to-geolocation mapping. Adobe Analytics will adopt this new dataset in the October, 2022 timeframe. The new database will be more accurate than previous versions. Some IP-to-geo mappings will change/improve when the new database is adopted."

[RobertBlakeley · Accepted solution]

I checked our data and I see a decrease in the NY and Chicago share of DMA Sept-Nov that that continues the longer term historical trend. This as opposed to the 2x increase you are seeing. 

Other DMAs (e.g. Atlanta, Washington DC) had some significant shifts (relative to our historical trend) in Dec, but not NY or Chicago. This likely has to do with our traffic patterns rather than Digital Element.

[LJiang]

Additional details to add - 

The site was also tracked under GA. the visits/sessions are similar across GA and AA. While the % of visits from NYC/Chicago were 2x higher in AA but not in GA. 

DMA	2H 2021	1H 2022	2H 2022	1H 2023
AA	GA	AA	GA	AA	GA	AA	GA
New York, NY	8.7%	7.2%	6.6%	6.4%	12.7%	6.2%	12.3%	5.4%
Chicago IL	3.8%	3.6%	4.5%	4.6%	8.5%	4.9%	7.0%	3.5%
Washington DC (Hagerstown MD)	3.7%	2.4%	5.7%	2.4%	6.1%	2.9%	3.2%	2.5%
Los Angeles CA	4.2%	4.1%	4.2%	3.9%	5.3%	3.6%	4.3%	3.2%
Atlanta GA	4.9%	4.2%	4.9%	3.6%	4.3%	3.6%	2.9%	3.4%