A quick perusal of Craigslist yields very few one bedrooms offered in Carlsbad for over $1600. Most are below $1500. Where are they getting an average of $1716? Are they only surveying large landlords?
Maybe you are right that $1716 is an overestimate because it avoids random small craigslist landlords.
But it doesn’t matter how they are calculating the average, as long as their method is consistent, then their result of rising rents is correct.