Motley Fool: New metric to measure store productivity?

NEW YORK — There may be a new metric to track retail success or failure, according to a Motley Fool article posted Wednesday — employees per thousand square feet. The metric helps draw a correlation between service and sales productivity. 

Fool author Jacob Roche observed that while Walmart has increased its total square footage by 23% between 2007 and 2012, the company only grew its workforce by 5% in that timespan. "As a result, stores are having trouble keeping shelves stocked and customers are taking their business elsewhere," he wrote. 

In 2012, Walmart fielded 2.1 employees for every 1,000 square feet. Another retailer, Safeway, had 2.2 employees per 1,000 square feet. Roche compared those numbers to Whole Foods, which predicates its business on a higher level of customer service and fields 5.7 employees per 1,000 square feet.