The compensation principle under tort law aims for a just and fair compensation of damages to the plaintiff. A proper assessment of damages is the key to achieve the objective of the compensation principle and it also plays a crucial role in a timely and cost-effective resolution in a tort action. Assessment of damages is a complex process involving, several factors such as the age of the plaintiff, nature of the injury, severity and duration of pain, disability, emotional suffering, loss or impairment of life, impairment of family, marital and social relationships, impairment of physical and mental abilities, loss of lifestyle, among others. The assessment pro cess becomes more complicated when the liability is unclear. In other words, when the defendant argues that the plaintiff was contributory negligent, and the assessment of damages must apportion a discount to reflect the negligent acts by the plaintiff. This article summarises the steps as set out by the courts to apportion the damages to the extent of the blameworthy conduct or negligent acts by either party.

Prior to the year 2000, the common law rule of “last clear chance” governed the assignment of liability in a contributory negligence situation. In simple terms, where the contributory negligence of a plaintiff and the fault of a defendant caused damages to the plaintiff and where one of them had a “last clear chance” to avoid the effect of the other’s fault and failed to do so. If the defendant was the one who had had the “last clear chance”, the plaintiff could recover damages for the whole of their loss despite their contributory negligence. If the plaintiff was the one who had the “last clear chance”, the plaintiff could not recover any damages despite the defendant’s fault.[1]

One of the problems with this rule was that it determines whether or not a party’s fault will be treated as an effective cause of a plaintiff’s loss, it is unnecessary and misleading, because the common-law rule that only a “proximate” cause leads to legal responsibility deals exhaustively and adequately with questions of causation. The rule is harsh to the plaintiff as it was an “all or nothing” scheme. It entirely relied on whom had the last clear chance to avoid the accident, either the plaintiff or the defendant, with the complete responsibility of the accident resting with that party. As such, Alberta Law Reform Institute (ALRI) made repeated recommendations to the legislature to repeal the above common law rule.[2]

The Contributory Negligence Act[3], (‘CNA’) abolished the “last clear chance” doctrine and Section 3.1 of the Act provides:

Last clear chance rule not applicable
3.1   This Act applies if damage is caused or contributed to by the act or omission of a person, whether or not another person had the opportunity of avoiding the consequences of that act or omission and failed to do so.

The CNA Act also provides that:

Apportionment of liability
1(1) When by fault of 2 or more persons damage or loss is caused to one or more of them, the liability to make good the damage or loss is in proportion to the degree in which each person was at fault but if, having regard to all the circumstances of the case, it is not possible to establish different degrees of fault, the liability shall be apportioned equally.

The Alberta Court of Appeal in Heller v Martens[4] (Heller) 2002 ABCA 122, at para 34, Madam Justice Fruman for the court noted that “Apportionment of fault between a contributorily negligent plaintiff and a negligent defendant under the CNA requires an assessment of the parties’ degree of departure from the standard of care.” Justice Fruman further noted that there are three options for the apportionment of liability:

  • apportionment based on fault,
  • apportionment based on causation, or
  • apportionment based on a blend of fault and causation[5]

Justice Fruman stated that apportionment based on fault, would be a conclusion driven by the specific wording of the CNA Act that apportionment is to be “in proportion to the degree in which each person was at fault”.  She stated that basing fault (only) on the extent to which each person’s conduct caused the damages confuses the threshold requirement for establishing contributory negligence (damage caused by the fault of two or more persons) with the apportionment requirement (make good the damages in proportion to the degree in which each person was at fault, based on all the circumstances).

Secondly, an apportionment based on causation is in any event problematic, because either the fault was the legally recognized cause of the damage, or it was not (referring J. Goudkamp and L. Klar, Apportionment of Damages for Contributory Negligence: The Causal Potency Criterion (2016), 53:4 Alta L Rev 849 at para. 35) She also noted that “Causation” is a necessary precondition to liability, but apportionment is based on fault. The causation approach to apportionment serves neither objective of tort law – to restore the plaintiff to the position he or she would have enjoyed but for the negligence of the defendant[6] and to compensate the injured and deter the tortfeasor.[7]

As such, Justice Fruman stated that the appropriate test to be applied in determining contributory negligence is the “Comparative Blameworthiness Approach”. This approach involves two steps[8]:

  1. the defendant must prove that the plaintiff was also negligent, and that the plaintiff’s negligence was a cause of the injuries.[9]
  2. Once this step is satisfied, the process of apportionment of liability can occur such that the “liability to make good the damage or loss is in proportion to the degree in which each person was at fault.”[10].

The second step analysis requires consideration of the following factors:

  1. The nature of the duty owed by the tortfeasor to the injured person.
  2. The number of acts of fault or negligence committed by a person at fault.
  3. The timing of the various negligent acts.
  4. The nature of the conduct held to amount to fault. A deliberate departure from safety rules may be more blameworthy than an imperfect reaction to a crisis.
  5. The extent to which the conduct breaches statutory requirements.[11]
  6. The gravity of the risk created.
  7. The extent of the opportunity to avoid or prevent the accident or the damage.
  8. Whether the conduct in question was deliberate, or unusual or unexpected; and
  9. The knowledge one person had or should have had of the conduct of another person at fault.[12]

In Robinson v. Williams (Estate of), 2007 ABCA 19[13], the Alberta Court of Appeal relied on Heller, and confirmed that it “settled the law deciding that the appropriate test to be applied in determining contributory negligence is comparative blameworthiness and NOT a causation test.”[14]

This article summarizes the evolution of law on apportionment of damages from the “Last Clear Chance” doctrine to the enactment of the CNA Act, and further to the development of the “Comparative Blameworthiness” approach. We keep an open eye on how the courts would be evolving the law in the future. Presently, a court’s finding of a just and equitable apportionment based on both blameworthiness and causation aimed towards the modern purpose of apportionment legislation will be the best approach to promote fairness and justice between the parties.

[1] Alberta Law Reform Institute: Last Clear Chance Rule [ALRI: Last Clear Chance Rule]: available online at ALRI website:

[2] ALRI: Last Clear Chance Rule (Supra)

[3] Contributory Negligence Act, RSA 2000, c C-27 [CAN Act] online Canlii:

[4] Heller v. Martens, 2002 ABCA 122 (CanLII) [Heller]

[5] Canadian Natural Resources Limited v Wood Group Mustang (Canada) Inc. (IMV Projects Inc.), 2018 ABCA 305 para 40.

[6] Athey v. Leonati, 1996 CanLII 183 (SCC), [1996] 3 S.C.R. 458 at 468

[7] Dobson v. Dobson1999 CanLII 698 (SCC), [1999] 2 S.C.R. 753 at 782.

[8] Heller (Supra) para 31.

[9] Heller (Supra) para 14.

[10] Heller (Supra) para 31.

[11] Heller (Supra) para 34.

[12] Carrero v Park, 2022 BCSC 582 (CanLII) para 181 (Aberdeen v. Zanatta2008 BCCA 420, Groves J. added factors 6 to 9.)

[13] Robinson v. Williams (Estate of)2007 ABCA 19, 401 AR 262 [Robinson]

[14] Robinson (Supra) para. 13

Article by: Veeren “Victor” Bagga, (Summer Student)