What defines a "balanced market" in sf rentals?

[Marian Smith]

What is a balanced market in sf rentals? I have been reading that a 6 month supply is "balanced" for sf sales. Texas has currently a 4-5 month suppply for sale so is now entering a sellers market, supposedly. I looked back over the last year and in my zipcode about 11 houses rented per month. There are less than 30 for rent so a 3 month supply. Is that a "landlord's" market or are the ratios different for sf houses? Sf houses compete with apartments, obviously, so does one use the apartment vacancy rate to assess relative scarcity of available sf rentals? Thanks.