The data on Trulia, generally speaking, is composed of data feeds from a variety of sources. Any manipulation of the data it receives, if any, is a mystery to us.
Best to go right to the TEA site for accurate school ranking information.
When buying a home, the best place to start is to hire an Exclusive Buyer Agent. EBAs only work with homebuyers and there is never a conflict of interest that will jeopardize your negotiating position. Visit www.naeba.org for a referral to an Exclusive Buyer's Agent in your area.
I've had a book published on Amazon called Buying a Home: Don't Let Them Make a Monkey Out of You. It'll teach you how to buy a home without getting ripped off. Follow the link below.
Best of luck!