What sorts of comparison would best help you evaluate your carbon figures on Dopplr?

Hi Matt,

assuming that people enter their travel plans in DOPPLR when they are still provisional & not fully fixed, you can embed carbon footprint comparison in the trip entry process, linked with the transport medium selection. If somebody can see that the footprint of taking a plane is X times that of taking a train, they may change their mind and their travel plans if they still can. Of course, this make sense when you can offer viable alternatives (i.e. don't try to convince somebody flying from London to NY to take the train!).

That's the only reasonable comparison that I can think of - I can't see what you could compare a yearly (or monthly) total to. You could try to plot it against a distribution of carbon footprints of other travellers gathered through DOPPLR, but who's to say that this is representative of the whole population? If anything, it may be skewed upwards, and give people the illusion that their carbon footprint is as much as their peer group, and that's OK.

Hope this helps - disclaimer: I don't use the carbon feature as I think it's pointless to try and over-optimise life like that, so I may be missing something important here ;-)

Cheers,
Alex