Fuel economy is a reason to buy the 2013 Ford C-Max hybrid crossover, but not the only reason. That matters because critics have questioned how close the C-Max's real-world gas mileage comes to its eye-popping EPA rating of 47 mpg in the city, 47 on the highway and 47 in combined driving.

The first thing to remember is that the EPA rating is not a prediction. It's a comparison. It means the C-Max should get better fuel economy than a Toyota Prius v minivan – 42 mpg combined rating – but worse than the 50-mpg-rated Prius hatchback. The C-Max also beat the Honda Insight and Volkswagen Jetta hybrids.

The EPA rating is generated in a lab, not on the road. That's why you can compare one vehicle to another: they were all tested under identical conditions. If automakers apply the test honestly – I'm talking to you, Hyundai-Kia – it's the best way to compare vehicles' fuel consumption and cost.