How to research Canadian law on CanLII

Start with the question, not the search box

Good CanLII research begins away from the keyboard. Write your research question in a full sentence, then list the concepts inside it: the area of law, the parties or roles, the conduct or event, the remedy sought, and any jurisdictional or temporal limits. For each concept, list synonyms and alternative phrasings a court or drafter might use. Only then move to the search box.

Run three searches, not one

Plan a broad, balanced, and narrow pass:

• Broad. Any single core concept, sometimes with a synonym joined by OR. Use it to map the landscape, spot leading cases, and discover vocabulary the courts actually use.
• Balanced. Two or three key concepts joined by AND. Use it to find decisions squarely on point.
• Narrow. The balanced query plus exact phrases, proximity operators, or filters. Use it to isolate a specific fact pattern, sub-issue, or statutory provision.

Compare the three result sets. A useful decision often surfaces in the broad and balanced results even if the narrow query misses it, and vice versa.

Search operators to know

CanLII supports several operators for structuring a query. Confirm each one on the current CanLII Help pages before you rely on it, because the site’s syntax evolves.

• Exact phrases. Wrap consecutive words in straight double quotes, for example "duty of care".
• Boolean. AND narrows a query, OR broadens it, and NOT excludes terms. Group with parentheses, for example (negligence OR nuisance) AND "municipal liability".
• Proximity. /n looks for two terms within n words of each other, /s within the same sentence, and /p within the same paragraph.
• Wildcards. Use only the wildcard characters currently documented in CanLII Help. If you are unsure, spell out the variants using OR instead.

Document text vs case title and citation

CanLII lets you search the full text of a document or restrict the search to the case title or citation. Full-text is right when you are hunting for a rule, a phrase, or a fact pattern. Title or citation searches are right when you already know a party name or the neutral citation and simply want to retrieve the decision. Mixing the two in one session, starting broad in full-text and pivoting to a title search once you know the leading case’s name, is often the fastest route.

Filter by jurisdiction, court or tribunal, and date

After the first pass, refine using the filters CanLII exposes in the results panel: jurisdiction (federal, or a province or territory), court or tribunal, and date range. Filters change the size and shape of a result set materially; record which filters you applied so you can reproduce a search later. Do not apply so many filters at once that a genuinely relevant decision is filtered out.

Searching legislation and cases

Legislation and cases are separate collections on CanLII. When looking for a statute or regulation, search legislation directly by title or by section keywords, then confirm the version in force on your date of interest. When you have found the provision, run a full-text case search for the section number, often combined with a topic phrase, to see how courts have applied it.

Noting up

Noting up means checking whether a case or provision has been considered, followed, distinguished, or overruled by later decisions, and whether legislation has been amended or repealed. CanLII provides tools that surface later documents citing a given case or provision. Read those later documents yourself; do not treat any count or label as a conclusion about current authority. This guide does not perform a note-up, and no automated tool replaces reading the later cases and the current version of the legislation.

Keep a research log

A short log makes research reproducible and honest. For each search, note the date, the collection, the exact query, the filters applied, the number of hits, and the promising results. Update the log when you refine a query. When you cite a case or a provision, note where you verified its current status. Institutional or professor rules may require a more formal research memorandum.

Evaluate results and check currency

For each promising result, ask five questions: Is it from the right jurisdiction? Is it from a court or tribunal whose decisions bind or persuade the court you care about? Is it on point on both law and facts? Is it still good law after later cases and amendments? Does the version of any legislation you are relying on match the date relevant to your problem?

Coverage limitations and what “no results” means

CanLII’s collections are extensive but not exhaustive. Coverage varies by jurisdiction, court, tribunal, and time period, and some historical or unreported decisions are not on the site at all. Read the CanLII Terms of Use and the collection notes for the court or tribunal you are researching. An empty result set on CanLII does not prove that no authority exists; it only tells you that your query, in the current collection, returned nothing. Confirm with another database, a print source, or a reference librarian where the answer matters.