Foot traffic volume is often the first number a site selection team reaches for when evaluating a candidate location. It is intuitive: if a lot of people pass through or near the site, there is a pool of potential customers. The logic is not wrong, but foot traffic alone is a starting point, not a conclusion. It answers the question of how many people are in the vicinity without telling you whether those people are your customers, whether the local market has enough unmet demand to support another location, or whether opening there would cannibalize a store you already operate.
Three metrics together give a more complete picture before you commit to a lease: trade area demand gap, cannibalization risk score, and competitive density index. Each captures something the others miss. Together, they cover most of the analytical ground between a foot traffic observation and a confident lease decision.
Metric 1: Trade Area Demand Gap
A demand gap is the difference between what consumers in a trade area spend in your retail category and what the available category supply in that area can absorb. A positive gap, where demand exceeds supply, indicates an undersupplied market. A negative gap indicates oversupply.
To calculate this, you need two inputs. The demand side comes from combining trade area population with category spending rates drawn from consumer spending data. For a specialty apparel retailer evaluating a metro suburb, this might mean taking the total number of households within a 12-minute drive, applying the category spending rate for that demographic profile, and arriving at an estimate of total annual category spending in the catchment.
The supply side requires calculating how much category retail square footage already operates in that catchment and what annual revenue it is likely generating. Competitor locations, their estimated size, and their estimated productivity rates give you a supply estimate. The difference between the two is your demand gap estimate.
A large positive gap does not automatically make a site viable. The gap needs to be large enough to support your format's required volume, and you need to account for your own cannibalization before treating the gap as fully capturable. But a site with a negative or minimal demand gap is a warning signal that the market is already fully served, and adding supply into an oversupplied catchment is a volume-transfer game, not a new demand capture game.
Metric 2: Cannibalization Risk Score
Cannibalization risk measures how much of a new location's projected volume would come from customers who already visit one of your existing stores. A location with high foot traffic and a strong demand gap may still be a poor choice if a large share of that demand is already being captured by a location you operate.
The cannibalization risk score is best calculated using a gravity model rather than a radius rule. A gravity model estimates the probability that a customer from each origin zone within the trade area would choose the new location over an existing one, based on the relative proximity and attractiveness of each. It handles geographic barriers, road network asymmetries, and the difference between customer behavior in dense versus sparse markets more accurately than a simple distance threshold.
The output is expressed as a cannibalization rate: of the new location's projected annual visits, what percentage would represent customers migrating from existing locations rather than genuinely new customers? For most chains, a cannibalization rate below 20 percent on the projected visit volume is generally manageable, though the acceptable threshold depends on the performance of the stores being cannibalized and the volume of genuinely new demand the site captures. A high-performing store absorbing significant cannibalization from a nearby opening is a different situation than a marginal store losing some volume to a stronger new location.
Metric 3: Competitive Density Index
Competitive density measures the degree to which direct competitors are already present in the trade area. This is not the same as the supply-side component of the demand gap calculation, which estimates total category capacity. Competitive density specifically measures how many well-positioned competitors you would be entering against, how established they are, and how much of the foot traffic to your category in the trade area they are already capturing.
A competitive density index can be constructed by counting the number of direct competitors within the trade area, weighting by their estimated category market share in that geography, and normalizing against the total estimated category demand. A market with high category demand and one established competitor that has modest market share presents a different competitive situation than a market with similar total demand split among four well-established chains, even though both might register as "competitive" on a simpler count-based measure.
One important nuance: high competitive density is not always a disqualifying signal. In some categories and some markets, competitive clustering is a positive indicator because it suggests that the market has established consumer awareness of the category and that there are enough category visits to support multiple operators. A site evaluation that automatically filters out high-competitive-density markets may eliminate some of the most productive locations in major metros. The useful question is whether the competitive density is consistent with adequate market demand and whether you have a differentiated enough position to capture share.
Using the Three Together
Each of these metrics can produce false signals in isolation. High foot traffic with a negative demand gap and high competitive density is a very different situation from high foot traffic with a positive demand gap and low competitive density, even though both register as "high foot traffic sites." The demand gap, cannibalization risk, and competitive density metrics together paint a much clearer picture of whether a site's foot traffic is accessible, incremental, and defensible.
A site that scores favorably on all three dimensions is not a guaranteed success. Lease terms, store operations, local marketing, and execution matter significantly. A location scoring well on demand gap, cannibalization risk, and competitive density narrows the range of outcomes substantially, but it does not remove them entirely. These metrics give you better inputs for the decision. The decision itself still requires judgment about factors the data does not fully capture.
Teams that track these three metrics consistently across their candidate pipeline will find, over time, that they get better at predicting which locations will perform at or above target and which will disappoint. That predictive improvement is the value of building a consistent evaluation process rather than treating each site as a unique judgment call.