Jury Instructions: Comprehension Problems and Linguistic Remedies

The linguistic features that cause comprehension failures in jury instructions are not accidental. They are the direct result of a drafting culture that prioritises legal accuracy and appellate reviewability over communication. A pattern instruction must survive challenge from experienced appellate lawyers who will scrutinise every word for technical error. No one scrutinises it for comprehensibility.

Charrow and Charrow (1979) conducted the foundational linguistic analysis of jury instructions, testing comprehension by asking mock jurors to paraphrase what they had heard. They identified several grammatical structures that consistently produced high error rates. Their analysis is still cited because the problem they documented has not fundamentally changed in many jurisdictions.

• Nominalised constructions: 'The preponderance of the evidence standard requires the determination by the trier of fact' instead of 'The jury must decide which side is more probably right'.
• Passive voice: 'Evidence may be considered if it was offered for a proper purpose' leaves unclear who considers it and what proper purpose means.
• Double negatives: 'Failure to comply does not necessarily preclude a finding in favour of the party who failed to comply.' Three negatives in one sentence create a parsing problem even for attentive readers.
• Mismatched legal and everyday meanings: 'Malice', 'assault', 'battery', 'negligence', and 'intent' all have everyday meanings that differ from their legal definitions. Jurors import the everyday meaning unless the instruction explicitly and accessibly corrects them.
• Long sentences with multiple embedded clauses: Instructions that specify an element, then an exception, then a qualification on the exception, then a cross-reference to another instruction, all in a single sentence, exceed working-memory capacity for most listeners in an oral delivery.

Reifman, Gusick, and Ellsworth (1992) surveyed actual jurors in Michigan civil and criminal cases about their understanding of the instructions they had received. Correct understanding of the relevant criminal legal issues was achieved by only 41 percent of criminal jurors. Kramer and Koenig (1990) found that jurors who received standard Michigan criminal instructions on specific intent correctly applied the standard on less than half of case scenarios designed to test it.

The pattern is consistent across studies and across jurisdictions. The problem is not that jurors are inattentive or unintelligent. The problem is that the instructions require processing abstract legal concepts under oral-only delivery at the end of a fatiguing trial. Even well-educated jurors in controlled experiments show systematic failure on specific instruction elements.

The Charrow and Charrow analysis identified grammatical features; later work by Diamond and Levi (1996), Tiersma (1999), and Dumas (2000) extended this to look at concept-level barriers that survive even grammatically simpler re-writes. A jury instruction can be rewritten into short, active sentences that are still deeply confusing because the underlying legal concept has no natural-language analogue.

• Reading level mismatch: Most pattern instructions score at 12th grade or above on Flesch-Kincaid. The average US adult reads at about 8th grade. A level gap of four grades is associated with comprehension rates below 50 percent for orally delivered text.
• Oral-only delivery: Instructions are typically read aloud at the close of trial and not provided in written form in most US jurisdictions. Oral processing of complex syntactic material without a reference text is inherently less accurate than reading, and jurors cannot pause or re-read.
• Context-free delivery: Instructions are usually read as a block, removed from the evidence they govern. Jurors must mentally re-connect abstract legal standards to the specific facts, an additional processing step that increases error.
• Legal-everyday word conflict: When a legal term matches a common word, jurors apply the common meaning without realising the legal definition differs. 'Malice' in everyday usage implies personal hatred; in criminal law it often means intentional conduct without justification, a significantly wider category.

The controlled literature on rewritten instructions is substantially more optimistic than the baseline comprehension data. Charrow and Charrow themselves produced improved versions of their test instructions and found that addressing the grammatical features they identified produced comprehension gains of 10 to 50 percentage points depending on the instruction. Subsequent researchers have found similar or larger gains for specific elements.

Several jurisdictions have undertaken systematic plain-language rewrites of their pattern instruction sets. California replaced its longstanding CALJIC instructions with the CALCRIM set in 2005, developed with input from linguists and cognitive psychologists. Arizona redesigned its civil and criminal instructions in the 1990s and made them available in written form to deliberating jurors. Studies comparing before-and-after performance under these revised systems find consistent improvements in juror application accuracy.

• Sentence simplification: Breaking multi-clause sentences into single-proposition sentences. Effect: consistent 10-20 percentage point comprehension gain in controlled studies.
• Vocabulary replacement: Substituting everyday equivalents for legal terms where the legal meaning is the same. Effect: variable, largest for terms like 'malice' and 'deliberate', smaller for terms where the legal meaning requires a new concept rather than just a different word.
• Active voice: Rewriting passive constructions to name the actor. Effect: consistent but modest, approximately 5-15 percentage points; larger when the actor's identity is itself legally significant.
• Written copies for jurors: Providing written instructions for use during deliberations. Effect: moderate comprehension improvement, larger when combined with plain-language rewriting.
• Pre-instruction: Giving jurors the key standards at the start of the case rather than only at the end. Effect: consistent improvement, particularly on burden-of-proof standards; jurors can apply the standard to evidence as it arrives.

Forensic linguists have contributed to jury instruction reform in both the research phase and the implementation phase. Researchers like Bethany Dumas and Peter Tiersma published analyses of instruction comprehensibility that fed directly into the California CALCRIM reform process. The National Center for State Courts in the US has engaged linguists to develop testing protocols for new instruction sets.

In the UK, the Law Commission's 2013 and subsequent reports on jury directions drew on psycholinguistic evidence, and the Judicial College's 'Crown Court Compendium' (updated annually) incorporates plain-language guidance developed with academic input. The Australian AIJA (Australasian Institute of Judicial Administration) produced best-practice guidelines for jury instructions that reference linguistic research on comprehension.

Individual expert witnesses also appear in post-conviction proceedings where a defendant argues that incomprehensible instructions deprived them of a fair trial. These cases are rare and rarely succeed in the US, because courts apply a presumption that jurors understood and followed the instructions as given. But in jurisdictions with fuller disclosure of juror deliberation records, linguistic analysis of deliberation transcripts has occasionally revealed systematic instruction misapplication documented in real time.

Given the strength of the evidence that current instructions frequently fail, the pace of systematic reform in most jurisdictions requires explanation beyond the merits of the evidence alone. Several structural factors explain the resistance.

Pattern instructions are drafted by committee and revised through a process that requires consensus among appellate lawyers who care primarily about what the instructions say, not about whether a juror without legal training will understand them. Any change to a settled instruction opens the possibility that a reviewing court will interpret the change as having altered the legal standard, which then risks reversals until the new language builds its own appellate track record.

There is also a deeper institutional reluctance to acknowledge that the system has been delivering verdicts under instructions that jurors did not understand. If incomprehensible instructions were formally acknowledged as a structural problem, it could undermine confidence in verdicts reached under old formulations. The path of least resistance is to treat comprehension as the jurors' responsibility rather than as a system design problem.