Canada: Causation, Causation, Causation — Is What's Old New Again Or Are Times A "Changing"

First presented at the CDL Fall Classic.


"Study the past if you would define the future" - Confucius

Just as Confucius guided us so many centuries ago, similarly, in order to understand the concept of causation in accident benefits context, we must look to the past.

The year is 2008. The case of Monks v. ING Insurance1 had now reached Justices Cronk, Gillese and Watt of the Court of Appeal for Ontario. Justice Cronk writing for the unanimous Court summarized the jurisprudence on causation in accident benefits matters to that date:

[85] Athey v. Leonati2 is the leading Canadian case on causation in tort law. In Athey, Major J. reiterated the following well-established principles:

(1) The general, but not conclusive, test for proof of causation is the "but for" test, which requires a plaintiff to show that his or her injury would not have occurred but for the negligence of the defendant (paragraph 14).

(2) In certain circumstances, where the "but for" test is un-workable, causation may also be established where it is demonstrated that the defendant's negligence "materially contributed" to the occurrence of the tort victim's injury. It is not necessary for the plaintiff to establish that the defendant's negligence was the sole cause of the injury (paragraphs 15 and 17).

(3) Liability will be imposed on a defendant for injuries caused or materially contributed to by his or her negligence. That liability is not reduced by the existence of other nontortious contributing causes (paragraphs 22 and 23).

Although tort law clearly limited the use of the "material contribution" test, the accident benefits jurisprudence continued to use it in many instances as the appropriate test for causation. In Monks, Cronk J.A. stated:

More recently, in Resurfice Corpo. v. Hanke3 ... the Supreme Court of Canada clarified the exception to the "but for" causation test and the circumstances in which the material contribution test may be applied. I do not understand Resurfice to alter the basic causation principles that I have described.

Since 2009, both the Court of Appeal and the Supreme Court of Canada indirectly raised scepticism about the jurisprudence supporting the "material contribution" test as the default test in accident benefits matters.

In Clements (Litigation Guardian of) v. Clements,4 Chief Justice McLachlin stated the following:

The legal issue is whether the usual "but for" test for causation in a negligence action applies, as the Court of Appeal held, or whether a material contribution approach suffices, as the trial judge held. For the reasons that follow, I conclude that a material contribution test was not applicable in this case. I would return the matter to the trial judge to be dealt with on the correct basis of "but for" causation.5

As for the "material contribution" test, the Chief Justice McLachlin observed:

The idea running through the jurisprudence that to apply the material contribution approach it must be "impossible" for the plaintiff to prove that the defendant's negligence caused the plaintiff's injury using the "but for" test has produced uncertainty in this case and elsewhere.6

Finally, in Blake v. Dominion of Canada General Insurance Co.7 Brown J.A. applied the "but for" test in an accident benefits case. He reasoned his decision based on the fact that the plaintiff counsel did not ask the trial judge to depart from the general "but for" test of causation. In other words, Brown J.A. implied that, without specific request and justification, the "but for" test remained the default test in accident benefits matters as it continued to be in the tort context.

The "But-For" Test

It is a basic principle of the law of negligence that it is not sufficient for a plaintiff to merely demonstrate that a defendant had acted negligently; it must also establish that the defendant's negligence is what caused the plaintiff's injury.8 The onus lies on the plaintiff to establish causation as a probability and it is insufficient to merely demonstrate that the defendant's negligence caused the plaintiff injury.9 The proof of causation is a necessary element of negligence, as "a defendant in an action in negligence is not a wrongdoer at large: he [or she] is a wrongdoer only in respect of the damage which he [or she] actually causes to the plaintiff."10

The test for establishing causation is the "but for" test, which requires the plaintiff to prove on the balance of probabilities that the defendant's negligence was necessary to bring about the injury.11 The "but-for" test has almost universal acceptance as an instrument for ascertaining causation. The formula postulates that the defendant's fault is a cause of the plaintiff's harm if such harm would not have occurred without (but for) it.12

The "Material Contribution" Test

As outlined in Clements, the basic rule of recovery for negligence is that the plaintiff must establish on a balance of probabilities that the defendant caused the plaintiff's injury on the "but for" test. However, there are certain rare instances when the plaintiff might be entitled to recovery for negligence on the basis of "material contribution" test. This can occur in cases where it is impossible to determine which of a number of negligent acts by multiple actors caused the injury, but it is established that one or more of them did in fact cause it. In these rare instances, the underlying public policy initiatives prohibit the defendant from escaping liability by shifting the blame at another wrongdoer. Therefore, Courts allowed for the defendant to be found liable on the basis that he or she materially contributed to the risk of the injury.

As set out by Smith J.A. in MacDonald (Litigation Guardian of) v. Goertz13

... "material contribution" does not signify a test of causation at all; rather it is a policy driven rule of law designed to permit plaintiffs to recover in such cases despite their failure to prove causation. In such cases, plaintiffs are permitted to "jump the evidentiary gap"... That is because to deny liability "would offend basic notions of fairness and justice".14

However, in accident benefits context "material contribution" test has taken on a different meaning then in tort law. As explained by Director's Delegate Evans, the use of the "material contribution" test has caused confusion at the Financial Services Commission of Ontario ("FSCO") because:

[material contribution] has a specific meaning in tort cases, as set out in Resurfice, but in cases at the Commission it means that a cause of the disability — injuries arising from a motor vehicle accident — is materially contributing to the disability despite other causes, whether they arose before or after the accident.15

Therefore, it is important to note that the "material contribution" test is not the default test for proving causation in accident benefits context and it should only be utilized where it is impossible to determine which of a number of negligent acts by multiple actors caused the injury.

Mere Temporal Relationship ≠ Causation

The Courts have urged against making inferences of causation based on a mere presence of temporal relationship. In other words, where causation is supported by the fact that an injury appeared or worsened after the accident, there should be close scrutiny of all the evidence available and the inference that causation is satisfied should not be drawn from the temporal relationship. The decisions below shed further light at the dichotomy between causation and temporal relationship and caution against inferring causation from a mere presence of temporal relationship.

In White v Stonestreet,16 a plaintiff was involved in a motor vehicle accident. However, the plaintiff had a pre-existing degenerative condition and the Court cautioned against inferring a causal connection from a temporal one. The plaintiff's experts claimed that since the plaintiff did not have lower back pain before the accident but developed lower back pain after the accident, the accident must have been the cause. The Court rejected this claim.

Furthermore, in Rollins v. English Language Separate District School Board,17 the plaintiff was a six year old girl who was struck in the head by swinging rollerblades in the schoolyard. Later that evening, the plaintiff became sick and her eye was twitching. She went into convulsions the following day and was eventually diagnosed with Rasmussen's encephalitis.

The plaintiff's doctor theorized that the blow to the head by the swinging rollerblades caused blood brain barrier long enough to allow antibodies to cross over and attack her brain. As a result, the plaintiff brought an action against the school board and the principal for breaching their duties of care. However, the Court held that there was no reliable scientific evidence to conclude that mild brain trauma was causative factor in onset of Rasmussen's encephalitis. Further, the Court held that there was no reliable evidence upon which it could draw an inference that the blow to the head by swinging rollerblades resulted in Rasmussen's encephalitis. In other words, the Court refused to infer a causal connection from a temporal one.

Current State of Law

The current state of Canadian law involving the proof of causation is twofold. The plaintiff can prove causation by proving that he or she would not have suffered the loss through the "but for" test. In the alternative and in rare and exceptional circumstance, a plaintiff may prove causation by indicating that the defendant's conduct was "material contribution" to risk of the plaintiff's injury. Furthermore, in order to successfully utilize the "material contribution" test, the plaintiff must establish both of the following criteria:

(i) the plaintiff must establish that his or her loss would not have occurred "but for" the negligence of two or more tortfeasors; and

(ii) the plaintiff, through no fault of his or her own is unable to show that any one of the possible tortfeasors in fact was the necessary or "but for" cause of her injury.

In addition, proof of causation in accident benefits cases has been reconciled in Kofi Agyapong v. Jevco Insurance Company.18 In Agyapong, the issues were whether the Applicant was entitled to non-earner, and housekeeping and home maintenance benefits as a result of a motor vehicle accident in which he was struck by a pickup truck as a pedestrian. The Applicant had preexisting impairments including an industrial accident, a criminal assault, and two previous motor vehicle accidents.

Arbitrator John Wilson held that the Applicant did not meet the evidentiary burden of proving his entitlement to non-earner, and housekeeping and home maintenance benefits. More importantly, Arbitrator Wilson reviewed both the Supreme Court of Canada's decision in Clements and the Court of Appeal's decision in Blake and subsequently concluded that the "but for" test is not only the default test for proving causation in tort law but also in accident benefits cases, as well.

More recently, in Ms. K and State Farm Mutual Automobile Insurance Company, Arbitrator Feldman confirmed that the "primary test for causation in an accident benefits case remains the "but for" test" and that the "material contribution" test is only to be used where the "but for" test's application is impossible.19 This decision further supports the underlying conclusion that the "but for" test is to be the default test to prove causation in the accident benefits cases.


Through its lengthy history, the "but-for" test has proven to be worthy of its title as the default test for ascertaining causation. In proving causation, the "but-for" test is the default test in tort as well as in accident benefits cases and "material contribution" test is virtually non-existent. In the words of Arbitrator Wilson from Agyapong, "the days of the ritual application of the "material contribution" approach in accident benefit matters are numbered at best..."20


1 Monks v ING Insurance Co of Canada, [2008] 90 OR (3d) 689 (Ont. CA).

2 Athey v Leonati, [1996] CarswellBC 2295 (SCC).

3 Resurfice Corpo v Hanke, [2007] 1 SCR 333

4 Clements (Litigation Guardian of) v Clements, [2012] 2 SCR 181.

5 Supra at para 5.

6 Supra at para 35.

7 Blake v Dominion of Canada General Insurance Co, [2015] OJ No 1218 (Ont. CA).

8 Clements at para 6.

9 Rothwell v Raes, 1988 CarswellOnt 1085, paras 245 and 246; see also Edgar v. Richmond (Township), 1991 CarswellBC 800, at Para. 107

10 Mooney v. British Columbia (Attorney General), 2004 BCCA 402 (CanLII), 202 B.C.A.C. 74, at para. 157, affirmed by the Supreme Court of Canada in Clements v. Clements, [2012] 2 SCR 181, Para. 16.

11 Clements at para 8, 9 and 10.

12 March v Stramare [1991] 171 CLR 506.

13 MacDonald (Litigation Guardian of) v Goertz, [2009] 275 BCAC 68 (BCCA).

14 Supra at para 25.

15 Arunasalam v State Farm Mutual Automobile Insurance Co., [2011] O.F.S.C.D. No. 21, at para. 30.

16 White v Stonestreet, [2006] B.C.J. No. 1150 at paras 70, 71, 74 and 75.

17 Rollins (Litigation guardian of) v. English Language Separate District School Board No. 39, [2009] O.J. No. 6193.

18 Kofi Agyapong v. Jevco Insurance Company, FSCO A11-003445.

19 Ms. K and State Farm Mutual Automobile Insurance Company [2016] O.F.S.C.D. No. 127 at para. 25.

20 Agyapong, at paras. 64 and 65.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on

Click to Login as an existing user or Register so you can print this article.

In association with
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at and we will use commercially reasonable efforts to determine and correct the problem promptly.