One will find in Economics handbooks that "equitable distribution of income" is often seen as a macroeconomic objective.
The Gini cooefficient is the also often used to measure the achievement of this goal.
Apart from the issues involved in measuring equality, it may be useful to consider the following:
This quote… is from page 14 of Julian Simon’s Introduction to his brilliant 1995 edited volume, The State of Humanity (original emphasis):
Data on the absolute gap between yearly incomes of the rich and poor countries are beside the point; widening is inevitable if all get rich at the same proportional rate, and the absolute gap can increase even the poor improve their incomes at a faster proportional rate than the rich. Here one should notice that increased life expectancy among the poor relative to the rich reduces the gap in lifetime income, which is a more meaningful measure than yearly income.
Of course, the same holds true when speaking of the incomes of rich and poor individuals or families.
There seems to be a relationship between economic freedom and economic prosperity. Here is a link to the Heritage Foundation's Freedom index: http://en.wikipedia.org/wiki/Index_of_Economic_Freedom The Frasier Institute of Canada has a similar index. The conclusion that can be made as a result of these studies are that the goals of an economy can be met more effectively by lifting restrictions on trade.