Advan Changes to Trade Areas (cbgs) Normalization

Overview:

Starting with data from Nov 18, 2024 onward, visit data based on trade areas is normalized to better align with raw visit counts. (Fields: visitor_home_cbgs, visitor_home_aggregation, visitor_daytime_cbgs, visitor_country_of_origin)

Suggested action: It is suggested that users interpret these trade area values (at all time intervals) as ratios or scaled indicators rather than absolute numbers due to the impact of adjustments.

Background:

For visitations Advan uses a panel which is consistent across time and can be normalized, in order to generate accurate year-over-year growth metrics. For trade areas (e.g. visitor_home_cbgs, visitor_home_aggregation, visitor_daytime_cbgs, visitor_country_of_origin), Advan uses all the panels they are receiving, for which they have explicit permission to utilize for trade areas, as some panels prohibit Advan from computing where the cellphone spends its nights, i.e., the "home"; and its days, i.e., the "work" area. This is a much larger panel, which intersects but does not fully contain the visitation panel, as such it is more volatile month-over-month, so it should not be used for year-over-year comparisons (use the visitation metrics instead).

To account for this, Advan aligns the visitation & trade area fields by adjusting the trade area values as a percentage of the visitations, as the sum of the trade area fields would not equal visits/visitors otherwise (Advan does not have a home census block group assigned for each visitor).

Ultimately, Advan recommends that users interpret these trade area values as ratios or scaled indicators rather than absolute numbers due to the impact of adjustments (i.e., if one CBG has a value of 100 and another of 50, it means that the first one is about twice as large as the second one).

FAQs

What is the start date for this realignment?
November 18, 2024 (week start).

Is there a backfill for these changes?
No, there is no restatement.

How should the trade area numbers prior to the effective date above be interpreted?
The trade areas should always be interpreted as ratios/scaled indicators.

How is differential privacy applied?
Advan still removes single visit devices from TAs and rounds up 2, 3, to 4. However, since Advan scales TA visitors to visitors it may show as 1 in TA fields. This just means 4 is scaled down to 1. It does not mean "1" device. It means "4 scaled down to 1" since the panels are not the same; as such, the counts are just indicative.

For example, say you have 1 visitor and 1 visitor from a single TA:

• First, a POI that got only 1 device captured in the entire week (and more so in the entire month) cannot really be used for any kind of reliable statistic. It is just indicative.
• Further, given the visits and TA panels are not the same it is possible there were actually 2 devices and Advan rounded it up to 4 and then scaled down to 1. So, the devices are not exactly the same devices.
• Finally, the ratio is indicative that visitors from this POI come mostly from a given TA. However, since a POI with so few visitors is just indicative, it means that CBG is a likely source of visitors- no more than this.

For more information, review Advan’s documentation page. For any follow up questions, post in our Discussion forum.