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Similar fact evidence

Similar fact evidence is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Similar fact evidence rather than just read about it. In short: In the law of evidence, similar fact evidence (or the similar fact principle) establishes the conditions under which factual evidence of past misconduct of the accused can be admitted at trial for the purpose of inferring that the accused committed the misconduct at issue. By jurisdiction Canada In Canada, the rule was established in R. v.

Key takeaways

  • Similar fact evidence belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Similar fact evidence to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Similar fact evidence from memory before moving on to harder problems.

Reference excerpt

In the law of evidence, similar fact evidence (or the similar fact principle) establishes the conditions under which factual evidence of past misconduct of the accused can be admitted at trial for the purpose of inferring that the accused committed the misconduct at issue.

By jurisdiction

Canada In Canada, the rule was established in R. v. Handy, 164 CCC (3d) 481, 2 SCR 908 (2002): Evidence of prior bad acts by the accused is admissible if the prosecution satisfies the judge on a balance of probabilities that, in the context of the particular case, the probative value of the evidence in relation to a specific issue outweighs its potential prejudice and thereby justifies its inclusion. Questions arise as to how the Court is to measure the elements of this rule: i) What constitutes a prior act of misconduct?

Past misdeeds need not have resulted in a conviction. ii) Why does the Court speak of evidence in relation to a 'specific issue'?

Good measure of probity, what other issue beyond disposition or propensity evidence. iii) How is probative value determined?

Nature of similarity between details, distinctive features and circumstances of past and current offences Proximity in time between past and current offense Number of occurrences of the similar acts Any intervening event Any other factor tending to support or rebut the unity of past act and conduct in question (i.e. appearance of collusion)

England and Wales The 2001 trial of Roy Whiting may have influenced the decision to change the law in England and Wales (R v Handy continues to govern the law in Canada). These changes were brought into force by the 'Bad Character' provisions of the Criminal Justice Act 2003 (sections 98 to 113). Although preceding these changes, Rosemary West's 1995 trial was cited as an example where similar fact evidence was crucial to the prosecution case. Similar fact evidence can be used even if the original "misconduct" could not be prosecuted due to duress or the offender's youth. In a case of a Devon family imprisoned in 1998, one of the defendants appealed his conviction for raping his sister at age 16, suggesting it was unlikely that she would not complain or seek help. It was held that the evidence that his father had coerced him into sexual acts with his other sisters as a child was similar fact evidence and, in addition to the systematic long-term sexual activity and abuse within the family, sufficient to explain why he felt that he could get away with abusing her and knew she could not rely on her family for protection; his appeal failed. [R v TM, 2000, 2 Cr App 266]

New Zealand In New Zealand, the rules regarding similar fact evidence are codified by section 43 of the Evidence Act 2006.

Scotland Under Scots law, this is covered by the well-established use of the Moorov Doctrine.

United States Under Rule 404 of the United States Federal Rules of Evidence, evidence of a person's character or character trait is not admissible to prove that on a particular occasion the person acted in accordance with the character or trait. Additionally, evidence of a crime, wrong, or other act is not admissible to prove a person's character in order to show that on a particular occasion the person acted in accordance with the character. This evidence may be admissible for another purpose, such as proving motive, opportunity, intent, preparation, plan, knowledge, identity, absence of mistake, or lack of accident.

See also Doctrine of chances

References

External links Supreme Court Of Canada Case: R. v. Hardy R v M & others, Court of Appeal from Plymouth Crown Court

Worked examples

Example 1 — a first encounter with Similar fact evidence

Start with the simplest possible case. Write down what Similar fact evidence claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Similar fact evidence before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Similar fact evidence ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Similar fact evidence

In research
Similar fact evidence appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Similar fact evidence in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Similar fact evidence is common in secondary-school and first-year university syllabi. It links to neighbouring topics Evidence law, so understanding it makes those chapters shorter.
In everyday life
Look for Similar fact evidence outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Similar fact evidence in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Similar fact evidence means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Similar fact evidence out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Similar fact evidence in simple terms?

In the law of evidence, similar fact evidence (or the similar fact principle) establishes the conditions under which factual evidence of past misconduct of the accused can be admitted at trial for the purpose of inferring that the accused committed the misconduct at issue. By jurisdiction Canada In…

Why does Similar fact evidence matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Similar fact evidence?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Similar fact evidence.

Tags

  • Evidence law

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