My last book was titles 'Hiroshima'. This book was based on the events that followed several individuals after the bombing of Hiroshima.
What the book about is, alone, already far different from 'Freakonomics'. Frankly the only tie I see between the two is the Sumo Wresling and Japan. That and the fact that they're both non-fiction are the only similarities.
'Freakonomics' is based on american issues and, again, other then the sumo wreling and an iraqy nursery are the only foreign affairs mentioned.
In 'Hiroshima' the only thing that tied it to america was the Red Cross.
There's really not much to compare these two to.