Recent news reports have highlighted an increase in foot traffic for CostCo as the spread of the coronavirus spurs
people to stock up on essentials. Some analysis has put the number of visitors to CotsCo stores in the US up 72%
year-over-year.

At Advan, we ran a detailed analysis of true foot traffic at CostCo. The graph below shows average daily traffic for
each month since October 2015, with year-over-year changes overlaid.

According to our data, CostCo saw an increase in traffic of 11.5% compared to last March. This number is in line with
CostCo's published revenue growth. It also well within the range of growth that CostCo has shown in the past.

What drives these large differences in our reports versus past published reports? The reality is, it takes a lot of hard
and detailed work to derive accurate measurements. Here is what Advan has done to arrive at the above numbers:

• Manually geofence every single CostCo, and its parking lot, separately. Have 2 QA teams verify that the correct
  locations are geofenced.
• Capture and verify the opening and closing dates (although the latter is not applicable in CostCo's case) of each of these
  locations.
• Parse the hours of operations of each location, so that any data points before or after store hours are not included
  in the analysis
• Procure multiple data sources, test their consistency and performance historically, choose which ones to combine and
  how.
• Normalize the data to remove collection, geographical and other biases.
• Verify that the data is correct versus published CostCo revenue: 0.89 year over year correlation over the last 3
  years

Each of the above is a major undertaking, both in time and effort. But that is what is necessary and distinguishes a
correct analysis from a claim that can be completely off the mark. It is common knowledge, but worth repeating: "half
knowledge is a dangerous".