If you want a quick guide what may be misleading about the influential book, The Spirit Level, it worth listening to this interview with Peter Saunders, Professor Emeritus of Sociology at Sussex University.
This debate is highly important. If it were true that the crucial thing for measures of the well-being of a society was, as The Spirit Level suggests, the level of equality, then such equality might rationally become a target of policy. But, having heard Professor Wilkinson, author of The Spirit Level, and heard also his critics such as Peter Saunders, it seems that the book’s case is not soundly based.
Go to this link and then look for the radio item:
What’s wrong with The Spirit Level?
ABC Radio National Counterpoint interview, 21 September 2011
I once heard an interview about this. The author said that if Britain had the same inequality level as Sweden then the murder rate would be lower. The interview pointed out that we already have a lower murder rate.