Self-storage facilities in the US

From 2010 to 2023, the United States added storage facilities at a steady clip, reaching approximately 50,000 nationwide, while the British public was being charged progressively more for the privilege of a pint of lager. This is either a profound statement about the nature of excess — Americans store their surplus, Britons drown theirs — or it is simply two nations doing what they do best, independently and expensively. The r of 0.9678 suggests that every new U-Store-It in suburban Ohio corresponds to a few pence added to a Wetherspoons menu. Economists call this 'coincidence.' The data calls it something much more alarming.

Both trends are driven by inflation, rising real estate costs, and consumer behavior shifts in their respective countries over the same 13-year window. US self-storage grew alongside suburban sprawl, downsizing baby boomers, and e-commerce inventory needs, while UK pint prices rose due to increased duty, energy costs, staffing inflation, and post-Brexit supply chain pressures. Both metrics are ultimately proxies for the cost of physical space and labor in developed Western economies during a period of sustained inflation. The correlation is strong precisely because both series are non-stationary upward trends during a shared era of rising costs.

Long-run upward trends are the single greatest generator of spurious correlations in economic data — any two things that generally increase over a decade will produce impressive r-values without sharing a single causal thread. This particular pairing is a monument to the fact that 'both went up' and 'one caused the other' are statements separated by an enormous philosophical gulf.