What Is a Presumption in Evidence Law?
A presumption is a rule that forces the fact-finder to reach a specific conclusion once an underlying “basic fact” is established — for example, that the registered owner of a car was its driver. That makes it fundamentally different from a permissive inference, which the jury may, but doesn’t have to, draw.
This topic is one of the highest-value, most misapplied areas on the California Bar Exam, because the federal default rule and the California rule genuinely diverge — not just in wording, but in outcome.
A presumption is a mandatory rule requiring the fact-finder to find a presumed fact once a basic fact is proven, unless and until the presumption is properly rebutted. How much rebuttal it takes — and what happens after — depends entirely on which jurisdiction’s rule applies.
Burden of Production vs. Burden of Persuasion
Before you can analyze any presumption, separate these two burdens:
- Burden of production — the obligation to come forward with enough evidence to get an issue to the jury at all. Fail this, and the judge can direct a verdict against you on that issue.
- Burden of persuasion — which party loses if the evidence ends up in equipoise. This burden generally does not shift during trial.
Civil cases use a preponderance-of-the-evidence standard, with narrow exceptions (fraud, undue influence, and rebutting the community-property presumption) that require clear and convincing evidence. Criminal cases require proof beyond a reasonable doubt on every element.
FRE 301’s Bursting-Bubble Theory
Under federal law, FRE 301 gives presumptions a modest effect: a presumption shifts only the burden of production to the opposing party. Once that party offers any credible rebuttal evidence, the presumption “bursts” — it disappears entirely, and the jury weighs the underlying evidence as if the presumption never existed, with no special instruction about it. This is the “bursting bubble” theory, and it’s the federal default outside diversity cases (where FRE 302 sends courts to state law instead).
California’s Two-Track System: CEC §§ 602–606
This is where the exam-critical divergence lives. California doesn’t use one uniform bursting-bubble rule. Instead, CEC § 601 splits every presumption into “conclusive” (irrebuttable) or “rebuttable,” and then splits rebuttable presumptions again into two tracks that behave completely differently.
| Feature | Presumptions Affecting the Burden of Producing Evidence (CEC §§ 602–604) | Presumptions Affecting the Burden of Proof (CEC §§ 605–606) |
|---|---|---|
| Purpose | Facilitates resolution of this particular case | Implements independent public policy (e.g., favoring marriage, parentage, community property) |
| Effect once opponent produces contrary evidence | Presumption disappears — jury weighs the evidence normally | Presumption does NOT vanish; it shifts the actual burden of persuasion to the opponent |
| Federal analog | Matches FRE 301’s bursting-bubble effect | No federal analog — FRE 301 has no equivalent burden-of-persuasion-shifting presumption for state-law claims outside diversity/FRE 302 |
| Example | Registered-owner-was-driver presumption | Community-property presumption for assets acquired during marriage |
The presumption that property acquired during marriage is community property is the textbook example of the second track: the spouse claiming separate property must prove that claim by clear and convincing evidence — the presumption survives mere contrary evidence and controls the outcome unless persuasion actually shifts. Under FRE 302, this California rule even follows into federal diversity cases where state law supplies the rule of decision.
Sandstrom v. Montana and Criminal Presumptions
Presumptions get constitutionally dangerous in criminal cases. In Sandstrom v. Montana, the Supreme Court held that a mandatory presumption shifting the burden of persuasion to a criminal defendant on an element of the offense violates due process — it would let a jury convict without the prosecution proving every element beyond a reasonable doubt.
Permissive inferences, by contrast, are constitutionally fine as long as there’s a rational connection between the basic fact and the inferred fact. Prosecutors can shift a defendant’s burden on an affirmative defense, but never on an element the state itself must prove.
Worked Example: The Registered Vehicle
Priya is struck by a car registered to Devon. Priya proves the registration, triggering the presumption that the registered owner was the driver. This is a presumption affecting the burden of producing evidence — it exists purely to help resolve this particular case, not to advance any independent public policy.
Devon testifies the car was stolen that morning and offers a police report. Once Devon produces this credible rebuttal, the presumption bursts under both FRE 301 and CEC §§ 603–604 — federal and California law reach the identical result here, and the jury simply weighs who was driving without any instruction about the presumption.
Now change the facts: instead of a car accident, the dispute is whether funds used to buy a house during Priya and Devon’s marriage were separate or community property. California’s community-property presumption is a burden-of-proof presumption under CEC §§ 605–606. Even after Devon offers contrary evidence, the presumption doesn’t vanish — Devon must actually prove the separate-property claim by clear and convincing evidence. Under FRE 301’s bursting-bubble default, by contrast, that same presumption would disappear the moment Devon produced credible contrary evidence. This is exactly the trap California bar examiners set.
Common Mistakes on the Bar Exam
- Applying FRE 301’s bursting-bubble theory across the board in California. Only CEC §§ 602–604 presumptions behave that way; §§ 605–606 presumptions shift actual persuasion.
- Confusing a mandatory presumption with a permissive inference. “You must find” shifts a burden; “you may infer” shifts nothing.
- Forgetting Sandstrom in criminal-law essays. A presumption that shifts persuasion to a criminal defendant on an element is unconstitutional.
- Failing to state which burden shifts. Every presumption essay answer should explicitly identify whether production, persuasion, or nothing shifts — and why.
Frequently Asked Questions
What’s the difference between a presumption and an inference?
A presumption is mandatory — the fact-finder must find the presumed fact once the basic fact is shown, absent rebuttal. An inference is permissive — the fact-finder may, but need not, draw the conclusion.
Does California always follow the federal bursting-bubble rule?
No. Only presumptions affecting the burden of producing evidence (CEC §§ 602–604) burst like the federal default. Presumptions affecting the burden of proof (CEC §§ 605–606) shift actual persuasion and survive mere contrary evidence.
Can a presumption shift the burden of persuasion to a criminal defendant?
Not on an element of the crime — Sandstrom v. Montana holds that unconstitutional. Only a permissive inference, or a burden shift on an affirmative defense, is allowed.
Key Takeaways
- Burden of production (getting to the jury) and burden of persuasion (who wins in equipoise) are distinct, and presumptions can shift either.
- FRE 301 uses a bursting-bubble theory: any credible rebuttal evidence makes the presumption disappear.
- California splits presumptions into two tracks — CEC §§ 602–604 (production, bursts like federal law) and §§ 605–606 (persuasion, survives rebuttal).
- The community-property presumption is the classic CEC §§ 605–606 example, requiring clear and convincing evidence to rebut.
- Sandstrom v. Montana bars mandatory presumptions that shift the burden of persuasion to a criminal defendant on an element of the offense.
This article is educational and is not legal advice. Consult a licensed California attorney about your situation.
Related guides
- community property definition and presumptions
- res ipsa loquitur burden shift
- residual hearsay exception
- dead man’s statute and witness competency