Tuesday, May 27, 2008

Group differences - within and between - pick a standard please!   posted by TangoMan @ 5/27/2008 01:59:00 PM

The debate over at The American Scene on Jim Manzi's article "Undetermined" is now closed to comments so I couldn't respond to one of the comments but the beauty of being a blogger is that you can use your own forum to vent your response.

The comment that I desperately wanted to respond to was left by Joe Shipman and reads as follows:
One thing that is established beyond any possibility of scientific doubt, of course, is that the genetic variability in IQ within races is much larger than the variability between races; any ethnic group of nontrivial size will have plenty of smart people and plenty of dumb people, and basing, say, educational policy on group rather than individual characteristics is therefore not only unAmerican but scientifically misguided.

Joe, will you join with me in advocating the complete dismantling of efforts to ameliorate the racial and gender wage gaps that exist, in that they too demonstrate that wage variability is larger within groups than between groups? I hit on this topic a few years ago:
It is important to recognize that most wage inequality occurs within and not between groups. The unweighted average Gini coefficient across all race, gender, and education groups was 0.256 in 1995, over 80 percent of the total Gini. Put another way, if all groups had identical mean wage rates (for example, black male dropouts had the same average wages as white male college graduates) but wages differed within groups as they do today, nearly all the inequality in wage rates would remain.

You know, if it's unAmerican and unscientific to craft social policy on observed group differences then surely the fact that the variability in Black or Hispanic incomes is greater within their groups than it is between their group and, say, Caucasians or Asians, is an unscientific and unAmerican basis upon which to craft social policy to address the between group differences in income. What's good for the goose is good for the gander, right Joe?