Originally Posted by Yahoo! Autos

Hybrid rankings have often been simplistic: Most are little more than lists of the highest-mileage models on the market. Here, we ranked hybrids based on how much fuel savings they get when compared to their non-hybrid version, as well as how much all that saved gas is going to cost you. Examinations that compare hybrids to "comparably equipped" versions miss an important point. Hybrids are almost always among the most expensive trim levels, if not the most costly, but our premise is that you're looking for efficiency first, followed closely by price. This isn't about acceleration, so the hybrids are compared to the lowest-priced, most-efficient gas-only trim level in their model line. Our rankings take into account the hybrid's mileage and price premium, in percent, as well as its suggested retail price. This gives less-expensive models a boost while penalizing more-expensive ones.