Supreme Court of Canada Decisions’ “Half-Life” Daniel Poulin (CRDP/Lexum inc.) & Philippe Grand’Maison (CRDP) Faculté de droit, U. de Montréal

Summary Approach: counting citations in case law Objectives: part science, part business Discussion of results Challenges

THE APPROACH

Case life-cycle Awakening: from publication on to the apex Apex: the year when a case is the most cited Death: year of the last known citation Length of life: from the time a decision is rendered until it is cited for the last time Half-life: form the apex to when the number of citations is half the value at apex

Hypothetical life of case ApexHalf life Number of citation per year Time

Long awakening; and local apexes Ithaca Daniel/long réveil

Cases with a “life” Percentage of decisions from 2002 having been cited Ithaca Daniel/Pourcentage cité

Methodology Data was arranged in decision’s vectors, decision-cite-decision, and metadata; For each decision, the following data is retrieved or calculated – Year first time cited – Year of apex – Apex value, the maximum # citations in a year; – Year of half-life (for decisions with over 50 cit.) – Year of last time cited

Challenges The data obtained from Lexum was estimated “messy” by one of the authors – The Reflex database was never thought as a tool for compilation, everything is geared towards adding link as cases get in The heavy calculation for building the life- cycle table fried the computer motherboard of one of the authors

Challenges The first tack was to limit the study to the Supreme Court of Canada – A couple months delay in a scanning project results in having to work with a more limited set of data: from 1949 on … instead of from 1907 With the more general citation data from the whole CanLII Compilation, the scope is even shorter

Did the law changed? In Katsh, M.E., “The new electronic media and the transformation of the law” (1989) Katsh hypothesized that – […] there will be more and more decisions cited on both sides of an issue… […] – [O]pinions are being added to the computerized database more and more quickly. This increase the pressure to use recent cases […] (p. 46)

What citations say about law? Could citations tell us something about the Canadian legal system? Are the changes in the constitutional framework in the case law citation?

How much case law history do lawyers need? CanLII was planned as a professional tool Historical scopes on CanLII today – Supreme Court: 105 years – Courts of appeal: 22 years – Superior courts: 16 years Is it enough? What more is needed from the past? What must be added?

The data Lexum’s SCC collection – 5600 decisions Lexum’s “CanLII compilation” – ~ 1,1 M decisions – 110,000 decisions from courts of appeal – 245,000 decisions from superior courts Reflex database – Millions of records Main limit – 83% of the decisions are from after 2000

CanLII Compilation Ithaca Daniel/Nombre de décisions par an

SOME OF THE RESULTS

Number of citations per decision Philippe /Ok. #cit par jugt parannée

Number of citations per decision Philippe /Ok. #cit par jugt parannée

AS HYPOTHESIZED, THE NUMBER OF CITATIONS AUGMENTED SIGNIFICANTLY WITH THE ADVENT OF NEW DIGITAL MEDIA

Awakening – Time to be known Philippe /Eveil dans le temps

Awakening – Time to be known Philippe /Eveil dans le temps

AWAKENING HAVE SHORTENED THE ACCELERATION STARTED EVEN BEFORE THE ADVENT OF NEW IT

Evolution of the age of citations Philippe / Âge des ref par année

Major legal events shorten lives

WHAT IS CITED – OLD V. RECENT CASES – SEEMS MUCH MORE SENSITIVE TO THE LEGAL CONTEXT THAN TO THE TECHNOLOGICAL CONTEXT

The shortening of half-life Philippe / Ok. demie dans le temps

The shortening of half-life ?! Philippe / Ok. demie dans le temps

FOR LACK OF HISTORICAL SCOPE, THE DATA SET CANNOT LEAD TO ANY CONCLUSION ABOUT THE HALF LIFE OF JUDGMENTS

QCCA citing ROC-CA Philippe / QC CA

ROC-CA citing QCCA Philippe / QC CA

ROC-CA & QCCA Philippe / QC CA

QUEBEC CA IGNORES CANADIAN CA, BUT LESS THAN CANADIAN CA IGNORE QCCA IT MUST BE NOTED THAT QUEBEC PRIVATE LAW IS DISTINCT FROM THE COMMON LAW TRADITION IN THE OTHER CANADIAN JURISDICTIONS

Citations to historic decisions ( ) Ithaca Daniel/07-11 # vers décennie

Citations to historic decisions ( ) Ithaca Daniel/07-11 # vers décennie

Citations to historic decisions ( ) Ithaca Daniel/07-11 # vers décennie

CITATIONS TO OLDER DECISIONS ARE FEW HOWEVER, THE TAIL COULD BE LONG

Summing up As hypothesized with the advent of new IT – The number of citations has augmented – Awakening have shortened Contrary to what was hypothesized – The age of the citations relate much more to the legal context than the technological one Quebec CA ignores Canadian CAs, but less than Canadian CAs ignore QCCA

Summing up This data set cannot lead to any solid conclusions about the half life of judgments However, – 0,5 M recent decisions cite only hundreds of cases from the 50s and the 60s – Almost as many from the 50s than the 60s