As MoveOn is popular around here these days, I thought I would share with you a MoveOn petition asks Congress to change to metric: http://petitions.moveon.org/...
So how is promoting metric a progressive value?
For one thing, promoting metric makes it easy to teach measurement. This is especially important for students who are not naturally good at this part of math and for students who attend schools that lack resources. It is difficult, if not impossible, to test the ability to measure through a multiple choice test. This means that measurement is pushed to the part of the school day that is not devoted to teaching to the test. The length of that time varies by school district and sometimes by individual school.
A school district that can afford to buy the books from Pearson (http://www.theatlantic.com/...) that contain the answers, can spend less time on test prep than a poorer school district. Richer school district usually buy physical objects to help teach kids math concepts. (Interestingly, the measurement materials that many companies sell along with its books may be metric only, as they are based on international templates.) This means that teachers can spend time teaching kids the basic skills that make up measurement.
Poorer schools often buy cheaper books that may be great for teaching kids skills that they will need and about the world around them, but don’t teach the kids what they are supposed to say on the tests. As a result, teachers may have to spend a lot of time on test prep. Those teachers may have no rulers or measuring cups (http://www.dailykos.com/...), let alone the math blocks and other things that teachers in wealthier school districts have access to.
And that is before the extra year that is added to our elementary math curriculum just so kids can understand our system.