"KBK" have proved such a constant combination that they usually only require one other judge to decide the case. The other four justices – Stephen Gageler, Geoffrey Nettle, Michelle Gordon and James Edelman – seem to almost take turns in joining them.

In the three most recent judgments, KBK combined once with Justice Gageler, once with Justice Gordon and once with justices Nettle and Gordon.

Yet earlier in the year, three out of a run of five judgments saw Justice Edelman join KBK for a single opinion that decided the case.

Solid bloc

The solid bloc calls to mind a comment by former High Court justice Michael McHugh about another influential trio during his time on the court: justices Mary Gaudron, Bill Gummow and Kenneth Hayne.

"Gummow and Hayne always seemed to come together – and they usually had Mary ... so long as those three were there, it didn't matter what they decided. They would pick up either [Ian] Callinan or [Michael Kirby],'' Justice McHugh said.

The end result is that the court is delivering a majority single opinion in around three of every four cases. This delivers the kind of certainty that many observers look for in our top court.

In one of the few cases that KBK could not persuade another justice to join them – Unions NSW – the court ended up with five separate judgments, with the other four judges all writing alone.


The trend brings the High Court closer to the Supreme Court of the United States , where a justice is usually designated to write a majority opinion.

Meetings

Chief Justice Kiefel has given a series of speeches in which she has emphasised the efforts the court makes to come together. They include meeting more often as a court during the preparation of judgments.

"We have now found that if views are divergent or there is no clear majority, so long as another meeting is arranged in a short period of time, that problem may be overcome," said the Chief Justice in one address.

"We are also finding that further meetings, where we can concentrate on the 'sticking points', tend to be quite fruitful."

Chief Justice Kiefel has also been one of the court's busier judges, having been involved in 26 of the 29 judgments.

Justices Gageler and Edelman are still the most likely to go it alone even if they agree with the orders by the majority. Justices Nettle and Gordon are more likely to write with each other if they are not part of a Kiefel-led judgment.