I remember my shock upon first researching the New York City office market. The average price per square foot seemed impossibly high, even for one of the most expensive markets in the world. After a quick search I found out that New York leases calculate rental price per square foot on an annual basis. This made every rent I looked at twelve times higher than an identical California property, where we use a monthly metric.
This is a fairly simple example, but it drives home the point of how different commercial real estate data can be. Since historically most commercial property deals are done with local representation, discrepancies in data were never that consequential. That was until the world started connecting using a technology that we now know as the internet.