The area of Dunedin has changed over time due to various political changes, we got rid of counties, it's now ~3300 sq km (don't know what that is in bananas, they don't grow here) - that's about 80 times the size of Berkeley (somewhere else I have lived). The population hasn't changed much.

However area is irrelevant since they chose everyone in the original city who was born during that period, the identity of the people they are studying hasn't changed

Remember when these guys were starting the software for this study, they were using cards.

Can you give that to me in football fields?