THE SCALE JUSTICE HOLDS IS BINARY, IS IT NOT?

A Mathematician Crunches the Supreme Court's Numbers (NICHOLAS WADE, June 24, 2003, NY Times)

The voting pattern of the Rehnquist court over the last nine years "shows that the court acts as if composed of 4.68 ideal justices," says Dr. Lawrence Sirovich, a mathematician at the Mount Sinai School of Medicine in Manhattan whose day job is figuring out how the visual system works.

By another measure, "the decision space of the Rehnquist court requires only two dimensions for its description," he writes in the issue of The Proceedings of the National Academy of Sciences being published today.

Nine independent thinkers who focus solely on the merits of cases might be expected to vote in all possible combinations over a long enough period. Dr. Sirovich's analyses indicate that the Supreme Court voting falls a long way from that pattern.

His first measure entails considering that if two members were twins who always voted the same way, the court would effectively have eight members, not nine. On a court with nine members, there are 512 possible voting patterns, or half that number if a vote is marked as being in the majority or not.

But the actual number of voting patterns is very much less, as if generated by a smaller number of wholly independent individuals.

Analyzing nearly 500 opinions issued since 1995 - the court membership has not changed since Justice Stephen G. Breyer joined it in 1994 - Dr. Sirovich calculates, based on information theory, that 4.68 ideal justices would have produced the same diversity of decision making.

By ideal, Dr. Sirovich means a justice whose voting is uncorrelated with any other's. His measure, thus, points up the high degree of correlation in the court's voting pattern.

Is complete randomness really a desirable quality in a system of justice? Posted by Orrin Judd at June 24, 2003 7:39 PM