Analysis and Aggregation

FollowGraph is delivered at a geographic level. When you combine several areas into a trade area, region, or custom polygon, use a weighted average of index scores—not a simple mean—so larger populations don’t count the same as tiny ones.

Weighted Averages

Weighted averages usually describe the combined area more accurately than a simple mean. The weight is typically population or household count (from Census or your own controls).

Many users combine FollowGraph with mobile movement or visitation data. In that case, visit or visitor counts can be an appropriate weight.

The formula for a weighted average is shown below.

\[ Weighted \, Average = \frac{\sum (weight \times score)}{\sum weight} \]

Multiply each weight by each value across records. Sum these values and divide them by the sum of all weights to produce the weighted average across several areas.