The XO-1 was made to support then untested educational theories.

A model is the underlying thought process or untested theory which explains why the phenomenon occurs.

The popular but largely untested theory describes in five distinct stages how people deal with grief and tragedy.

So far, none of the 120 apartments have been sold, leaving the value-added theory untested.

Nothing ever satisfies her but demonstration; untested theories are not in her line, and she won't have them.

The lawyers realized they were putting their faith in an untested legal theory.

Not for many liberals, who assert that the Administration places far too much confidence in the largely untested theory of managed competition.

He said it was based on "a hope and a prayer and an untested theory."

He wanted to gamble on an untested legal theory.

"That's still an unknown and it's still an untested theory."