What happens when half a city's grocery spending vanishes overnight?

While RNZ reports households across New Zealand freezing their spending as power bills and rates climb, Timaru's grocery data has collapsed in ways that defy the national trend. In 2013, Timaru households spent $15,445 on food. By 2014, that figure had plummeted to $7,836. (Source: Stats NZ, food-price-index-detailed)

This isn't a gradual decline. It's not households tightening their belts or switching to cheaper brands. It's a statistical cliff that drops the city's grocery spending to its lowest point in 21 years, matching levels last seen in 1993 when New Zealand was a fundamentally different economy.

The trajectory makes no economic sense. From 2010 to 2013, Timaru's annual grocery spending climbed steadily: $14,599 in 2010, $15,309 in 2011, $15,343 in 2012, then $15,445 in 2013. That's a normal pattern for a regional city keeping pace with inflation and population changes. Then 2014 arrives and the number gets cut in half.

This isn't about cost-of-living pressures forcing families to eat less. You cannot halve a population's food consumption in twelve months without catastrophic consequences that would dominate every news cycle. No mass exodus happened. No economic collapse. No natural disaster.

What did happen is a data collection change. Somewhere between 2013 and 2014, Stats NZ altered how it measures or reports Timaru's grocery spending. The agency might have changed its sampling methodology, redefined its geographic boundaries, or switched which retailers it tracks. The result: a dataset that makes year-on-year comparisons meaningless.

This matters because policymakers, journalists, and researchers rely on these numbers to understand regional cost-of-living pressures. When Auckland's grocery bills climb to $15,553 annually, that's a real trend you can track and respond to. When Timaru's numbers drop by half, you're looking at a measurement artifact, not an economic reality.

The broader lesson: not every dramatic shift in government data reflects a dramatic shift in reality. Sometimes the methodology changes. Sometimes the definitions shift. Sometimes what looks like a crisis or a miracle is actually a spreadsheet getting rebuilt.

For Timaru families watching their actual grocery bills climb alongside everyone else's, the 2014 figure offers no useful information. It's a number that exists in isolation, disconnected from the lived experience of buying milk and bread and vegetables in a South Canterbury city where costs keep rising, regardless of what the historical dataset claims.