⚡ 10-Second Rule
Once you sign a final written deal, earlier side promises that fight the writing stay out.
🧒 ELI-10 Scene
Priya and her dad haggle all week about chores and allowance. On Sunday they write a chart and both sign it. Monday, Priya says, "But Thursday you promised ice cream too!" Dad taps the chart. "We wrote the whole deal down. Ice cream isn't on it." The signed chart is the final word on what they agreed. But Priya can still explain what a smudged word on the chart means. And if Dad tricked her into signing, the chart doesn't protect him.
⚖️ Actual Rule
When parties adopt a writing as the final expression of their agreement — an "integration" — the parol evidence rule bars evidence of prior agreements and contemporaneous oral agreements offered to contradict the writing. Under Restatement (Second) of Contracts §§ 209–210 and 213–216 (paraphrased), a completely integrated writing — one that is both final and exclusive — also bars evidence of consistent additional terms, while a partially integrated writing bars only contradictory terms, leaving consistent additional terms admissible. A merger clause reciting that the writing is the parties' entire agreement is strong evidence of complete integration, though under the Restatement approach it is not automatically conclusive. The rule never applies to agreements made after the writing, and it does not bar evidence offered to (1) interpret an ambiguous term, (2) establish a formation defense such as fraud, duress, or mistake, (3) show an oral condition precedent to the contract's effectiveness (Restatement § 217, paraphrased), (4) prove a collateral agreement supported by separate consideration, or (5) support reformation of a writing containing a scrivener's error. For sales of goods, UCC § 2-202 takes a more liberal approach: even a final writing "may be explained or supplemented" by course of performance, course of dealing, or usage of trade, and by evidence of consistent additional terms unless the court finds the writing was "intended also as a complete and exclusive statement of the terms of the agreement."
ELI-10 translation: the final signed paper beats earlier talk, but talk doing a different job can still come in.
[NJ-VARIANT: flagged for future Eli Explains NJ Law module]
🔍 Ask These Questions
- Is there a writing the parties treated as final? (Did they mean this paper to be the real deal?)
- Is it completely or partially integrated — is there a merger clause? (Is the paper the whole deal, or just the final part of it?)
- Is the offered evidence from before or at signing, or from after? (Later promises are a new deal — this rule ignores them.)
- Is the evidence offered to contradict the writing? (Words that fight the paper stay out.)
- Is it offered for an excepted purpose — ambiguity, a formation defense, a condition precedent, a collateral deal, or reformation? (Words doing a different job walk right in.)
- Is this a sale of goods? (Under the UCC, trade habits and past dealings can usually still explain the paper.)
⚠️ Bar Trap
Exam language: Examiners bait you into excluding evidence of fraud, duress, mistake, an oral condition precedent, or a subsequent oral modification "under the parol evidence rule." The rule bars none of these: formation defenses attack whether a valid contract exists at all, a condition precedent asks whether the deal ever took effect, and modifications made after the writing fall entirely outside the rule.
ELI-10: The rule only blocks old promises used to fight the final paper. It never hides trickery. And it never touches promises made after the signing.
🧪 Question
A homeowner signed a detailed written agreement with a contractor to build a backyard deck for $20,000. The writing contained a clause stating that it was "the complete and final agreement of the parties." Before signing, the homeowner and the contractor orally agreed that the contract would not become effective unless the homeowner obtained a zoning variance within thirty days. The variance was denied, the homeowner refused to proceed, and the contractor sued for breach of contract. At trial, the homeowner offers testimony of the oral understanding about the variance. The contractor objects under the parol evidence rule.
Should the court admit the testimony?
(A) No, because the merger clause establishes that the writing is a complete integration. (B) No, because the oral agreement contradicts the writing's unconditional obligation to build the deck. (C) Yes, because the evidence shows an oral condition precedent to the contract's effectiveness. (D) Yes, because the parol evidence rule applies only to contracts for the sale of goods.
Answer: (C). Evidence that the parties orally agreed the written contract would not take effect until a condition occurred is admissible notwithstanding an integrated writing; it goes to whether any enforceable contract ever became operative, not to varying the terms of one that did.
💡 Why the Wrong Answers Are Wrong
- (A) overreads the merger clause; even a complete integration cannot block evidence that the writing never became operative at all.
- (B) mislabels the evidence; a condition on the contract's effectiveness does not contradict the writing's terms — it addresses whether they ever sprang to life.
- (D) inverts the UCC's role; the rule applies to all integrated contracts, and UCC § 2-202 merely applies a more liberal version to goods.
- ELI-10: The misconception is treating the final paper as unbeatable. Proof that the deal never switched on was always allowed in.
