John Morden and I have been discussing the extent to which Canadian courts look at cases from other courts, and I referred him to the excellent work of Professor Peter McCormick on the Supreme Court of Canada in a series of articles and a book Supreme at Last.
McCormick published a series of tables on citation patterns which showed by rough decade (actually tracked by the presiding Chief Justice) what sort of cases the SCC was citing to.
The table below is my attempt to combine all of this data in a single image and show some trends. I’ve measured them by percentage of all cases cited. Obvious trends:
* the Charter changed everything
* the citation of US cases was a minor blip and is now declining
* Canadian law has become itself, and is free-standing as a body of law; less and less is there a Commonwealth or even a global common law
* English law has consistently declined and really stopped being a dominant source at the time of the Laskin Court
I strongly suspect that similar results would be shown if studies were made of the appellate courts.
What this chart doesn’t show is the explosion in the quantity of citations and the length of decisions. The second chart has the numbers annualized to avoid massive swings and show the trends more clearly.