Is it a better financial decision to rent or buy?

Zillow has published a study based on first quarter 2018 data that estimates how many years of home ownership would be required before it becomes less expensive to own than to rent.  Here's a quick breakdown of the Bay area counties:

Here's a sample of their data:

The entire article can be found at:
https://www.zillow.com/mortgage-learning/trends/breakeven-horizon/

There are all sorts of assumptions made when doing these calculations so use with caution.  Nevertheless, if a buyer can actually purchase a home in the Bay area and if they plan on holding it for 3-4 years minimum, it's likely they will come out ahead compared to renting a similar property, according to this study.

It's worth noting that the main part of the article compares the 25 largest "metro areas".  This phrase usual means "metropolitan statistical areas" as determined by the federal government.  For some reason the San Francisco/Oakland/Fremont MSA is not included and nor is Phoenix.  But a city like Portland is included even though the city of Portland its MSA are both smaller than San Francisco.  However, if you use the interactive map on the Zillow link above it provides data by county.