Market evaluation: How to factor in new construction sales?

[Matthew Samson]

Hi All. I'm diving into some of the public county-level Zillow data. One metric they provide is new construction sales, which I can use to calculate % of total sales and see whether that value is trending up or down.

My question is, in general is a market more or less desirable if there are a lot of new builds hitting the area? 

On the one hand, I can see it as a positive indicator, for example of market health and increasing suburbanization. On the other hand, it could also mean there are lots of other desirable houses hitting the market, making older properties less desirable and/or lowering demand. 

Would love to hear your thoughts!