Rights and Presumptions

Presumption of Innocence

S. 11(d) of the Charter says any person charged with an offence has the right to be presumed innocent until proven guilty according to law in a fair and public hearing by an independent and impartial tribunal.

Right to Silence

Ss. 7 and 11(c) of the Charter protect an individual from being made a witness against itself, thereby putting its life, liberty or security of the person at risk.


Rule 3.3-1 of the Rules of Professional Conduct requires a lawyer to hold client information in strict confidence and not to divulge any of that information except with the client’s consent or as permitted by law and only to the extent that it is necessary.

In civil law, where mutual disclosure of relevant information is required, sub-rule 30.1.01(3) of the Rules of Civil Procedure establishes a deemed undertaking that the parties and their lawyers will not use this information for another purpose than the proceeding for which it was obtained.


In criminal law, the defence has an ongoing right to request and receive disclosure from the prosecution pursuant to R v Stinchcombe, [1991] 3 SCR 326. (The prosecution doesn’t owe the defence disclosure unless the latter requests it.) The prosecution doesn’t have a reciprocal right to disclosure from the defence and may be surprised by the defence’s evidence at trial (i.e., trial by ambush is allowed for the defence).

In civil law, both parties have a mutual obligation to disclose relevant information at the discovery phase of the proceeding pursuant to sub-rule 30.02(1) of the Rules of Civil Procedure. Trial by ambush is forbidden.

Communication with Witnesses

General Rules

The following table summarizes the cans and can’ts of communicating with witnesses. Rules restricting communications with witnesses seek to avoid tampering with evidence, especially after a witness testifies.

Cans and Can’ts of communicating with witnesses

Can communicate with
  • any witness after disclosing your interest, since “there is no property in a witness” (the witness, however, doesn’t have to speak to a lawyer)
  • your witness during examination-in-chief but not cross-examination
  • an unsympathetic witness anytime
Can’t communicate with
  • a represented witness without its lawyer’s consent
  • jurors, directly or indirectly

Safe Rules

Two safe rules for communicating with witnesses are:

    • it’s best not to speak to witnesses during a trial
    • when in doubt if you can speak to a witness, seek the permission of the court or opposing counsel

Rules for Communicating with Your Witness

Phase Can discuss
Examination-in-chief Evidence unrelated to examination-in-chief
Between examination-in-chief and cross-examination Evidence unrelated to examination-in-chief
Cross-examination by opposing counsel N/A
Between cross-examination and re-examination Evidence unrelated to re-examination
Re-examination N/A

Rules for Communicating with a Sympathetic Witness

Phase Can discuss
Cross-examination Evidence unrelated to examination-in-chief
Re-examination by opposing counsel Evidence unrelated to re-examination

Rules for Communicating with an Unsympathetic Witness

Phase Can discuss
Examination-in-chief by opposing counsel Witness’ evidence
Cross-examination of opposing counsel’s witness Witness’ evidence
Re-examination by opposing counsel Witness’ evidence
How to Interrogate a Witness

Basic Courtroom Etiquette

    • Remind the witness to address the jury
    • Remind the witness to refer to people as Mr. or Mrs. rather than by their first name or nickname
    • If the witness gives you trouble–for instance, if it asks you questions or is being sarcastic–ask the judge to remind it not to be sarcastic or that you don’t have to answer its questions (don’t speak to the witness directly)

Examination of a Witness

The three phases of examination of a witness are, respectively, examination-in-chief, cross-examination and re-examination.

At examination-in-chief, only open-ended questions may be asked, which invite the witness to describe what happened. These questions cannot be leading, meaning they can’t make any suggestions or assumptions or be the types of questions that can be answered with yes or no, maybe or I don’t know.

At cross-examination, leading questions can be asked, which can make suggestions or assumptions. A well-crafted leading question will usually only be answerable by either yes or no. This is because it’s rarely to a party’s advantage to allow the witness to give details, explain itself or ask it questions whose answers it ignores, whence the expression: “Never ask a question to which you don’t know the answer.”

At re-examination, the re-examining party can only ask open-ended questions to clarify points that were raised during cross-examination.

Refresh Your Witness' Memory at Examination-in-Chief

Lawyer: What did you eat yesterday?

Witness: Subway.

Lawyer: Your honour, I would like to refresh the witness’ memory. (Judge allows it.) Mr./Madam Clerk, I would like to request exhibit A. (Clerk hands exhibit to lawyer, who hands it to the witness.) Mr. Witness can you read page 1, paragraph 3 of This Document to yourself? (Witness reads.) Now I ask you a second time: What did you eat yesterday?

Witness: Ah yes, it was McDonald’s.

Enter an Exhibit Into Evidence at Examination-in-Chief

Lawyer: What is the colour of your vehicle?

Witness: Blue.

Lawyer: What is the model of your vehicle?

Witness: Honda.

Lawyer: What is the year of your vehicle?

Witness: 1998.

Lawyer: What is the condition of your vehicle?

Witness: Good.

Lawyer: Mr./Madam Clerk, may I request the picture labeled as picture 1? (Clerk hands over picture 1 to the lawyer.) Do you recognize this vehicle?

Witness: Yes, that’s my car!

Lawyer: Mr./Madam Clerk, would you kindly enter picture 1 into evidence as exhibit A?

How to Impeach a Witness

A witness can be impeached by undermining its credibility or evidence. This can be done by

    • declaring the witness adverse/hostile, if it’s your witness
    • undermining the credibility or evidence of the witness at cross-examination, if it’s a witness for the opposing party
    • excluding the witness’ evidence by objecting to it

1. Declaration of Adverse/Hostile Witness

A lawyer can’t impeach its witness with bad character evidence, since the common law presumes a witness is called to be believed. See R v Paquette, 2008 ABCA 49 (CanLII). The lawyer can, however, impeach its witness by declaring it adverse or hostile.

“Adverse” means the witness is “opposed in interests.” See R v Gushue (No. 4) (1975) 30 CRNS 178 (Ont Ct J). A “hostile” witness is a kind of adverse witness who is “not giving her evidence fairly and with a desire to tell the truth because of a hostile animus towards the [calling party].” See R v Figliola, 2011 ONCA 457 (CanLII).

A declaration of adversity/hostility can be based on the witnesses’ demeanour or prior inconsistent statement (PIS). See R v McAllister, 2008 NSCA 103 (CanLII) and s. 9(1) of the Canada Evidence Act. The steps to declare an adverse/hostile witness are as follows:

Steps to declare an adverse/hostile witness

Step Application
Refresh the memory of the witness with the PIS Coffin Application
Seek court permission to admit the PIS for the truth of its contents KGB Application if the witness is absent or adopts a new version of events or Khan Application if the witness is unavailable or can’t remember
Seek court permission to cross-examine the witness on the PIS s. 9(2) of the Canada Evidence Act, aka Milgaard Application (voir dire)

Seek court permission to cross-examine the witness as an adverse/hostile witness

s. 9(1) of the Canada Evidence Act (voir dire)

Tidbits Regarding Objection

    • don’t object unless you’re sure (1) the objection is correct and (2) it protects your client
    • stand up fully and object clearly
    • you can exclaim: “Objection!” and then think about the objection as you stand up (this avoids the situation where you think past the limit to object, which is sometimes very short)
    • don’t object to displays of emotion (e.g., if the other party’s witness starts to cry), as the jury may hate you for it

2. Common Objections and Replies

Objections in general

Objection! Example or explanation Reply

[State objection]

Object to any fallacies, ambiguities, incorrect or misleading statements, inappropriate behaviour or non sequiturs that waste time, vex the court or don’t prove a material issue. The objection doesn’t have to have a name.

Show that the objection is incorrect or that the evidence serves another legal purpose than the objection presumes. E.g., if the evidence is called hearsay, the objection presumes it is submitted for the truth of its content. Thus, an appropriate reply would be that the evidence isn’t submitted for the truth of its content.

Common objections to the question

Objection! Example or explanation Reply

Complex question

Asks many questions in one, e.g. “Who else was there or came along?” If the witness answers: “John, James and Peter,” it’s not clear if they were already there or came there. These should be two separate questions.

“It’s all one question” or break it down into separate questions.

Hypothetical question

Asks the witness for a speculative answer, e.g., “If John was drunk, would he have murdered Jane?”

“It’s not speculation” (e.g., “The witness knows John very well”).


This is the classic all-purpose objection. It is the easiest to spam and must be used sparingly, as evidence is generally presumed to be relevant, unless it clearly has nothing to do with anything. The weight of evidence is left for the jury to decide.

“It tends to make a material fact more or less probable” (R v Cloutier).

Not a question

E.g., if opposing counsel simply asks the witness to read a passage during cross-examination.

“I was going to ask a question.”

Leading question

‘Yes or no’ questions are only allowed in cross-examination.

Rephrase the question, e.g. “Please describe . . .”

Loaded question

The question makes an unwarranted assumption, e.g. “Do you still beat your wife?” (assumes he beat his wife) “Why?” (assumes there is a reason) “What did he want?” (assumes he wanted something), etc.

  • “The question doesn’t assume that”
  • Rephrase the question

Misleading the witness

E.g., if opposing counsel misquotes the witness.

If true, correct yourself. If not, politely correct opposing counsel.

The question is vague

E.g., if the question is unclear or has multiple meanings, especially if it’s a ‘trick question’ to which any answer may seem to favour the opposing party.

Rephrase the question.

Badgering or arguing with the witness

E.g., if opposing counsel is too close to the witness, rude to the witness, not letting the witness answer the question, etc.

If true, stop it. If not, politely correct opposing counsel.

Common objections to the statement

Objection! Example or explanation Reply

Character evidence

“The accused is a bad person, therefore it’s guilty!”

“It goes to credibility” (this almost always lets you get away with character evidence).

Presuming facts not proven

Opposing counsel presumes a fact without proving it.

If true, correct yourself. If not, politely correct opposing counsel.

Self-serving evidence 

E.g., the witness quotes itself or its lawyer quotes it to bolster its credibility, e.g., “I told the cop I didn’t do it.”

“It’s not meant to bolster the witness’ credibility.”

Opinion or speculation 

The witness gives a speculative answer instead of describing what it heard or saw. Or, the witness gives an opinion for which it isn’t a qualified expert.

  • “It’s not speculation but an observation” (e.g., “I saw Mark standing about 20 m from Jane” could be an opinion or an observation)
  • “It’s not speculation but a reasonable inference” (e.g., “The bike was going about 10 km/h” could be a reasonable inference, as opposed to a mere opinion)
  • “It’s not an opinion. It describes the witness’ state of mind” (this almost always lets you get away with opinion evidence)
  • “This opinion doesn’t require a qualified expert” (e.g., the opinion that a person was drunk doesn’t require an expert, R v Graat)


“He said / she said” or any statement that isn’t (1) agreed upon by both parties or (2) available to cross-examine.

  • “It lets the witness tell a full story” (narrative hearsay)
  • “It shows the circumstances of the event” (circumstantial hearsay; this almost always lets you get away with hearsay)
  • “It’s necessary and reliable” (Principled Approach; see R v Khan)
  • “It’s not being submitted for the truth of its content”

3. Undermine the Credibility or Evidence of a Witness at Cross-Examination

Lawyer: What did you eat yesterday?

Witness: Subway.

Lawyer: But in your statement you say you ate McDonald’s.

Witness: No, it was Subway.

Lawyer: Your honour, I’d like to show the witness exhibit A. Is this statement under oath?

Witness: Yes.

Lawyer: What is the nature of this statement?

Witness: Yes.

Lawyer: What is the date of this statement?

Witness: Yes.

Lawyer: Is that your signature on the statement?

Witness: Yes.

Lawyer: What does the statement say.

Witness: “I had a delicious Big Mac at McDonald’s yester . . .” But wait!

Lawyer: No further questions your honour.

Admissible Evidence

General Rule of Admissibility

Relevant and material evidence is generally admissible unless:

    • there is an exclusionary rule
    • its prejudicial effect outweighs its probative value

Legal Relevance

Evidence has to be legally relevant. Legal relevance is determined by:

    • the material elements to be proved
    • the standard of proof, which is “beyond a reasonable doubt in criminal law” and “on a balance of probabilities” in civil law; this translates to a greater than 50 percent probability of responsibility in civil law and a greater than 90 percent probability of guilt in criminal law according to Blackstone’s ratio: “[B]etter that ten guilty persons escape, than that one innocent suffer”
    • whether the evidence “renders the existence or absence of a material fact in issue more or less likely;” see R v Truscott, 2006 CanLII 60337 (ON CA) at para. 22

Legal relevance may be distinguished from logical relevance to the extent that legal proof may not be the same as logical or scientific proof.

“It’s possible, but is it probable?”


Evidence must be material, which means it must be directed to a matter in issue.

Legal Necessity (Best Evidence Rule)

“Necessity is the search for the best evidence available.” See R v Starr (2000), 147 CCC (3d) 449 (SCC).

The Best Evidence Rule holds that original and direct evidence should be given precedence over indirect evidence and copies or simulacra. For instance, a copy of a document will not be admissible if the original exists.

“That’s the most important piece of evidence we’ve heard yet!”


Evidence is deemed to be reliable where

    • it is testable by cross-examination
    • there is an absence of motive to fabricate

See R v Khelawon (2006), 215 CCC (3d) 161 (SCC).

The corroboration rule in Scot’s criminal law requires evidence from at least two independent sources to support a material fact in order to rely on it to convict someone. The same rule is found in biblical law (Deuteronomy 17:6, Matthew 18:16 and Qur’an 5:106). While this is not necessary in Canada, it is very persuasive.

Inadmissible Evidence

General Rule of Exclusion

Generally, rules that exclude certain types of evidence do so

    • for policy reasons (e.g., because the evidence was illegally obtained)
    • because experience shows it tends to be misused (e.g., character evidence has led to many wrongful convictions)

Overwhelming Prejudice

A judge may exclude evidence whose prejudicial effect outweighs its probative value. The prejudicial effect of evidence refers to whether it will bias the jury or waste time or money. Its probative value refers to whether it makes the ultimate issue more or less probable. See R v Mohan, [1994] 2 SCR 9.

“With all due respect your honour, we don’t live in this courtroom now, do we?”

Character Evidence

Character evidence is evidence that only shows “the accused is the type of person likely to have committed the offence.” See R v G (SG), [1997] 2 SCR 716. This is called the Prohibited Inference and it is the primary rule of exclusion. See Morris v The Queen, [1983] 2 SCR 190.

Where the judge admits evidence as an exception to the rule against character evidence, it must direct the jury not to make a Prohibited Inference. See R v B(C), 2003 CanLII 32894 (ON CA) at para. 35.

‘Archie’s a good or bad boy’ isn’t admissible evidence unless the defence brings it up and the prosecution responds

“She ought to be locked up and never released” – the Prohibited Inference in a nutshell

Exception: Similar Fact Evidence

Similar fact evidence can be exceptionally used to prove the identity of a person if there is “a high degree of similarity” between the facts. See R v Arp, [1998] 3 SCR 339.

Princess Jasmine recognize Aladdin by his peculiar manner

Inspector Javert recognizes Jean Valjean as the only man he ever saw lift a cart

Exception: Third Party Witnesses

Since third party witnesses aren’t “charged with an offence” pursuant to s. 11 of the Charter, they don’t benefit from the presumption of innocence. As a result, all kinds of theories and evidence that are normally inadmissible, including character evidence, can be used to undermine or bolster their credibility, as long as it’s relevant and doesn’t waste the court’s time.

The reason for the relaxation of the rules of evidence toward third party witnesses is because it creates a major disincentive for them to testify if they’re impeachable. This helps to ensure that only unimpeachable witnesses take the stand. The cost of suggesting the defendant is guilty is that they can bring out all your dirty laundry and accuse you as easily as you accuse them.

For instance, in the trial of Casey Anthony, who was accused of murdering her daughter, her defence attorney suggested that her father George, who testified, molested her as a child, which explains her suspicious behaviour when she went partying while she knew her daughter was missing. No evidence was adduced to this effect. It’s entirely possible that George collaborated with the defence to acquit his daughter at the cost of his public image and reputation.

In a real court, Shae could be painted as an immoral woman as easily as she paints Tyrion as a murderer

Exception: Significant Probative Value

Character evidence may be admissible if it has “significant probative value” that outweighs its prejudicial effect. An example is sexual reputation evidence in rape cases, which is generally inadmissible character evidence. However, subs. 276(2) of the Criminal Code exceptionally allows this type of evidence for a “specific instance of sexual activity” if it is of “significant probative value” and is not susceptible to the Prohibited Inference that the accused is the kind of person to consent or who shouldn’t be believed.

The boy’s habit of lying about the wolf would be admissible character evidence in a trial for the loss of his sheep


Hearsay is an out-of-court statement that is offered to prove the truth of its contents. See R v Khelawon, [2006] 2 SCR 787 at para 35. It is basically a statement that can’t be tested by cross-examination.

Prosecuting Attorney: How do you know he killed the baker?

Witness: I heard a little bird say it.

Defence Attorney: Objection! Hearsay. (I can’t cross-examine the little bird!)

Exception: Necessary and Reliable

Hearsay may be admissible if it is necessary and reliable.

The modern Principled Approach to hearsay asks if the impugned evidence is necessary and reliable, unlike the traditional approach which asks if the evidence is hearsay and, if so, if it falls under an exception to the rule against hearsay. See R v Starr, [2000] 2 SCR 144.

The table below provides a list of indicia of reliability based on caselaw. See R v Czibulka 2004 CanLII 22985 (ON CA), leave to appeal to SCC refused [2004] SCCA 502. See also R v Starr, [2000] 2 SCR 144 at para 65.

Indicia of reliability

Significance as interpreted by the courts Indicia Classic examples
Signs the statement is inherently trustworthy
  • spontaneous
  • without suggestion
  • speaker had no motive to fabricate
  • speaker was of sound mental state
  • against the speaker’s interest
  • speaker is a young person who wouldn’t likely know about the  allegations
  • corroborating evidence
  • Spontaneous declaration (res gestae)
  • Dying declaration
Safeguards against inaccuracy or fabrication
  • statement made to public officials
  • statement was recorded
  • speaker knew the statement would be publicized
  • Declaration in the course of duty
Absence of motive to fabricate
  • speaker made the statement under oath
  • statement was recorded
  • statement made under cross-examination
  • speaker is available to be cross-examined about the statement
  • Declaration against pecuniary interest
  • Declaration against penal interest

Exception: Prior Inconsistent Statement

A prior inconsistent statement may be admissible for the truth of its content even if it’s hearsay, as it points to the fact the statement isn’t reliable.

Cheshire Cat: “What white rabbit?” Alice: “But you just said! . . .”

Opinion Evidence

Opinion evidence is presumptively inadmissible, since witnesses are only supposed to testify concerning what they heard and saw. Tal Golan writes that the principle that witnesses speak only “what they see and hear” is “very old and [has] its roots in medieval law” (2007, p. 37).

To quote a well-known proverb, which is especially true in justice:

Image result for opinions are like assholes

Exception: Expert Evidence

Expert evidence may be admissible if it satisfies the Mohan criteria (see table below) on a balance of probabilities. See R v Mohan, [1994] 2 SCR 9.

Mohan criteria for the admission of expert evidence

Admissible expert evidence must be Questions to ask
Legally relevant
  • Will it assist or confuse the jury?
  • Will it usurp the fact-finding role of the jury?
Necessary to assist the judge or jury
  • Is the subject-matter outside the experience or knowledge of the judge or jury?
  • Can the judge or jury come to their own reasonable conclusions without help?

See R v Abbey, [1982] 2 SCR 24.

Not subject to an exclusionary rule
  • Is it subject to a rule of exclusion besides the rule against opinion evidence?
Given by a properly qualified expert
  • Does the purported expert have special knowledge acquired through study or experience concerning the matter on which it will testify?

If the evidence purports to be scientific, then it is subject to “special scrutiny” under the criteria of R v J‑LJ, [2000] 2 SCR 600 at para. 33 (see table below), which adopts the American Daubert standard.

Scientific evidence is subject to “special scrutiny” because juries tend to be misled by the “mystique of science” and the admission of “junk science” is one of the main causes of wrongful convictions. See R v Béland, [1987] 2 SCR 398.

J-LJ criteria for the admission of scientific evidence

Criterion Rationale
Can and has the theory or technique been tested? “Scientific methodology today is based on generating hypotheses and testing them to see if they can be falsified; indeed, this methodology is what distinguishes science from other fields of human inquiry.”
Can and has the theory or technique been subject to peer review and publication? “[S]ubmission to the scrutiny of the scientific community is a component of “good science,” in part because it increases the likelihood that substantive flaws in methodology will be detected.”
What are the rate of error and standards of operation? No comment.
Is the theory or technique generally accepted? “A “reliability assessment does not require, although it does permit, explicit identification of a relevant scientific community and an express determination of a particular degree of acceptance within that community.” [. . .] Widespread acceptance can be an important factor in ruling particular evidence admissible, and “a known technique which has been able to attract only minimal support within the community,” . . . may properly be viewed with skepticism.”

Clearly an expert:

Clearly not an expert:


S. 13 of the Charter says incriminating evidence against a witness can’t be used against them in another proceeding, except in a prosecution for perjury or for giving contradictory evidence.

Self-crimination pushed beyond the limits:

Illegally Obtained Evidence

S. 24(2) of the Charter says that evidence obtained in a way that violates the Charter rights of the accused will be excluded if its admission would bring the administration of justice into disrepute.

R v Grant, 2009 SCC 32 says the court must consider if exclusion of the evidence would reduce the confidence in the justice system of a reasonable person who is aware of the relevant circumstances. It must further consider how exclusion of the evidence would impact society’s confidence in the justice system based on:

    • the seriousness of the Charter violation
    • its impact on the Charter rights of the accused and
    • society’s interest in finding out the truth about the case and judging it on its merits
Weight of Evidence

Credibility of a Witness

Jerome Frank wrote in 1946 that “[W]henever there is a question of the credibility of witnesses–of the believability, the reliability, of their testimony–then, unavoidably the trial judge or jury must make a guess about the facts” (p. 16). This guess typically involves a judgment of the witness’ IQ and moral fibre. However, research shows that judges’ and jurors’ ability to judge whether a witness is telling the truth is about 50 percent accurate (Spencer 2007 and Spark 2011), whereas transdermal optical imaging is about 85 percent accurate (see TEDTalk) and polygraph testing is about 90 percent accurate (Raskin 2014). Such evidence, however, is not allowed in court–not for any scientific reason, but because it usurps the constitutional fact-finding role of the judge or jury. See R v Béland, [1987] 2 SCR 398 at paras. 43-45.

The table below shows the qualities courts tend to consider to assess the credibility of a witness according to Nicholas Bala et al., based on caselaw. For a summary and analysis of caselaw on credibility assessment, see Alan Mewett & Peter Sankoff, Witnesses (Carswell: Toronto, 1991) c 11 and Casey Hill et al,  McWilliams Canadian Criminal Evidence (Aurora, ON: Canada Law Book, 2004) c 27. 

Qualities courts tend to consider to assess the credibility of a witness

Quality Description
Honesty Is the witness making a good faith effort to fully and accurately give evidence, or conversely, is the witness deliberately lying or at least not disclosing certain information?
Memory How accurate and complete is the memory of the witness?
Suggestibility Has the memory of the witness been distorted as a result of conversations or questions with others?
Demeanour The demeanour of the witness while giving testimony, including such matters as the manner of speech, pauses, physical demeanour and apparent confidence of the witness.
Ability to communicate How well does the witness understand the questions and how well is the witness able to communicate about the matters at issue?
Consistency Whether the witness tells a consistent story, or conversely, becomes self-contradictory. The (in)compatibility of the witness’s testimony with other evidence in the case.
Plausibility Whether the testimony “makes sense,” that is, how consistent is the testimony with the understandings of the trier of fact about what happens in the world and how people act in different situations.
Reputation Whether or not the witness has a general reputation for honesty or dishonesty.

Judicial Notice

Courts can take ‘judicial notice’ of common knowledge that doesn’t require proof, like the fact Ottawa is in Canada or the Criminal Code is federal law.

Stipulative Evidence

When parties agree to a fact, this is called stipulative evidence. Common law courts do not require evidence of stipulated facts, which they simply presume.

Common law courts are only concerned with issues in dispute, which they try to resolve by using the law, dispute resolution (such as negotiation, mediation or arbitration), or, in the final resort, a trial of the disputed laws or facts.

Corroboration of Evidence

While the corroboration rule (or ‘at least two witnesses per material fact rule’) isn’t obligatory in Canada for criminal cases like in Scot’s law, most judges and juries tend to find evidence more compelling (i.e., weightier) as more evidence corroborates it. For instance, in Canada a judge can find a material fact in a criminal case based on the testimony of a single witness. See R v G(A)2000 SCC 17 (CanLII).

Protection of the Rights of the Accused

The common law protects the rights of the accused, who is in a vulnerable position toward society and the administration of justice. Hence, in criminal law the interpretation of the law and facts that is most favourable to the accused will be preferred, even if there is a more plausible theory, provided the interpretation is reasonable. (Proof beyond a reasonable doubt means there is no reasonable interpretation of the law and facts in favour of the accused.)

In civil law, the plaintiff must present a more plausible interpretation of the law and facts than any alternative.

Examples of how the justice system favours the defendant are the contra proferentem rule in contract law and the presumption of innocence in criminal law.

Rights of the accused in criminal law include:

    • the presumption of innocence
    • the right to be informed of evidence
    • the right to remain silent
    • the right to be represented by a lawyer
    • the right to understand the trial (i.e., the right to a bilingual trial or an interpreter)

Wigmore Chart

How a judge or jury will weigh the evidence is anyone’s guess, although lawyers tend to be more familiar with judges than juries, which sometimes enables lawyers to predict judges (and sometimes juries) to a limited extent.

In the early 19th c. John Henry Wigmore, one of the leading authorities on evidence in common law, proposed a useful device called a Wigmore chart, which has unfortunately found little use in court. The use of Wigmore charts could help to make judges’ weighing of evidence more rational and predictable (and corrigible).

Predicting how juries will weigh evidence, on the other hand, is a lot harder since, unlike judges, very little information about them is available and they don’t have to give reasons for their decisions.


Bruce Spencer, “Estimating the Accuracy of Jury Verdicts” (2007) Journal of Empirical Legal Studies.

David Paciocco & Lee Stuesser, The Law of Evidence, 5th ed (Toronto: Irwin, 2008).

David Raskin & John Kircher, eds, Credibility Assessment: Scientific Research and Applications, 1st ed (USA: Academic Press, 2014).

Jerome Frank, Courts on Trial (USA: Princeton University Press, 1949).

Kwangbai Park’s “Estimating Juror Accuracy, Juror Ability, and the Relationship Between Them” (2011) 35:4 Law and Human Behavior 288.

Nicholas Bala et al, “Judicial Assessment of the Credibility of Child Witnesses” (2005) 42:4 ALR 995, 2005 CanLIIDocs 163.

Tal Golan, Laws of Men and Laws of Nature: The History of Scientific Expert Testimony in England and America (USA: Harvard University Press, 2007).