Jury Instructions: Comprehension Problems and Linguistic Remedies

Jury instructions are the legal rules that guide deliberation, but empirical research consistently shows that jurors misunderstand key standards like 'beyond a reasonable doubt'. This topic examines the comprehension failures and the linguistic fixes that work.

Last updated: 10 Jun 2026

At the end of a criminal trial, after days or weeks of testimony and argument, the judge reads the jury a set of instructions. These are the legal rules the jurors must apply to reach their verdict. They cover the burden of proof, the elements of the charged offence, how to assess witness credibility, and often half a dozen other doctrines. In most jurisdictions the instructions are read aloud, once, without a copy for the jurors to keep. Then the jurors are sent to deliberate.

The empirical research on what jurors actually understand from this process is, by legal standards, alarming. Studies conducted in the United States, United Kingdom, Australia, and Canada consistently find that jurors misunderstand central legal standards at rates that would trouble anyone who believes the system delivers justice through correctly applied law. Comprehension of 'beyond a reasonable doubt' in various studies ranges from roughly 30 to 70 percent depending on jurisdiction and instruction version. Specific intent, deliberate indifference, and the insanity defence show similarly poor rates.

Forensic linguists work on this problem in two modes. The first is research: documenting the comprehension failures, identifying their linguistic sources, and testing whether rewritten instructions perform better. The second is advocacy: working with law reform commissions and court systems to produce empirically tested plain-language alternatives to the pattern instructions that most jurisdictions use. Both modes involve the same basic method: treating jury instructions as a communication design problem with measurable success criteria, not as a drafting formality that only lawyers need to understand.

Key terms

Pattern jury instructions: Standardised model instructions approved by a state or federal judicial council for use across all cases of a given type. They are intended to ensure consistency and appellate predictability, but they are drafted by committee lawyers for legal correctness, not by communication specialists for comprehension.
Beyond a reasonable doubt: The criminal standard of proof in common-law systems. The prosecution must persuade the jury to this degree before a verdict of guilty can be returned. The US Supreme Court has held it is constitutionally required but has declined to define it further for jury use, a decision that research suggests increases juror confusion.
Preponderance of the evidence: The civil standard of proof, meaning more likely than not, sometimes glossed as 51 percent probability. Jurors often confuse it with reasonable doubt, applying criminal-standard thinking in civil cases or vice versa.
Deliberate indifference: Also called 'willful blindness' or 'conscious avoidance' in some jurisdictions: the doctrine that a defendant cannot escape knowledge of a fact by deliberately avoiding learning it. The phrase is technically precise but cognitively difficult: jurors must reason about what the defendant could have known but chose not to learn.
Specific intent: A mental state element requiring that the defendant not only performed the act but did so with the purpose of achieving a particular result. Distinguishing specific from general intent is a routine source of instruction misapplication by jurors unfamiliar with the legal taxonomy of mens rea.
Juror comprehension research: The empirical literature, primarily in psychology and linguistics, that measures how well mock or actual jurors understand legal instructions. Methods include post-instruction questionnaires, deliberation observation, and controlled experiments comparing original and revised instruction versions.

The anatomy of an incomprehensible instruction

Instructions are written for appellate judges, not for the people who must use them.

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.

Anatomy of an incomprehensible jury instruction: five linguistic features and their effects.

Empirical research: what jurors actually understand

The numbers are sobering across three decades of research.

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 reasonable-doubt standard was achieved by only 51 percent of criminal jurors. Kramer and Koenig (1990) found that mock jurors who received standard California instructions on specific intent correctly applied the standard on less than half of case scenarios designed to test it.

Instruction element	Comprehension finding	Source
Beyond a reasonable doubt	Correct understanding in 51% of criminal jurors	Reifman, Gusick & Ellsworth (1992)
Specific intent (California)	Correct application in under 50% of scenarios	Kramer & Koenig (1990)
Preponderance of evidence	Confused with reasonable doubt by 30-40% of jurors	Severance, Greene & Loftus (1984)
Deliberate indifference	Correctly applied by approximately 40% of mock jurors	Solan (1999)
Insanity (M'Naghten)	Accurate understanding in roughly 35% of jurors	Ogloff (1991)

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.

Causes: what makes instructions comprehension problems

Reading level is the headline, but it is far from the whole story.

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.

Plain-language remedies and what the evidence shows

Rewriting works, but the effect size depends on what is rewritten.

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 BAJI 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.

The role of the forensic linguist in instruction reform

From measurement to implementation: two distinct contributions.

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.

Why reform has been slow

Institutional inertia, appellate incentives, and the comfort of familiarity.

Given the strength of the evidence that current instructions frequently fail, the pace of systematic reform in most jurisdictions is hard to explain purely on rational grounds. 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.

Worked example

Testing a 'deliberate indifference' instruction in a drug trafficking case

A mock juror study reveals a systematic misapplication that a grammatical rewrite does not fully solve.

A defendant is charged with drug trafficking. The prosecution's theory is that the defendant did not actually know the bags in his car contained drugs, but was 'deliberately ignorant': he took deliberate steps not to look, while being aware there was a high probability drugs were present. The standard deliberate indifference instruction reads: 'You may find that the defendant acted knowingly if you find beyond a reasonable doubt that the defendant was aware of a high probability that the fact in question existed and deliberately avoided learning the truth.'

Mock juror test: Sixty mock jurors receive the standard instruction in a summary trial scenario. Post-deliberation questionnaires reveal that 38 percent understand 'deliberately avoided learning' correctly. Twenty-two percent think it means the defendant actively tried to destroy evidence. Forty percent apply it as meaning simple ignorance, treating non-knowing as the same as deliberate non-knowing.
Grammatical rewrite: The sentence is broken into four sentences. Active voice replaces passive. 'Deliberately avoided learning' is replaced with 'deliberately chose not to find out even though they suspected it was true'. The new version scores 61 percent correct comprehension: an improvement, but still a third of jurors are wrong.
Conceptual explanation added: A two-sentence explanation is prefixed: 'The law says you can find someone knew something if they suspected it was true and on purpose chose not to check. This is to prevent defendants from escaping knowledge by choosing not to look.' The combined instruction scores 79 percent correct.
Lesson: Deliberate indifference is a genuinely non-intuitive legal concept. Grammar alone cannot carry the whole load; a brief conceptual explanation is also needed. The study documents the baseline, tests the remedies, and gives the court system data to justify a rewrite that includes an explanation the old instruction lacked.

Check your understanding

Question 1 of 4· 0 answered

What did Charrow and Charrow's (1979) foundational study of jury instructions find?

Key Takeaways

Jury instructions are drafted for appellate correctness, not lay comprehension, producing reading levels and grammatical structures that exceed what most jurors can decode under oral-only delivery at the end of a long trial.
Empirical research finds correct application of key standards, including beyond a reasonable doubt, specific intent, and deliberate indifference, below 50 percent in multiple studies across jurisdictions.
The causes include nominalisation, passive voice, double negatives, legal-everyday word conflicts, oral-only delivery, and conceptual difficulty that survives grammatical simplification.
Plain-language rewrites, particularly when combined with brief conceptual explanations, written copies, and pre-instruction, produce consistent and substantial comprehension improvements in controlled studies.
Systematic reform has been slow because appellate stability concerns, institutional inertia, and the professional culture of legal drafting all prioritise language correctness over communication effectiveness.

Why do jurors struggle to understand jury instructions?

Jury instructions are drafted by lawyers for appellate review, not for lay comprehension. They use passive constructions, legal jargon, multi-clause sentences, and abstract standards that everyday language does not use. Jurors hear them orally, once, at the end of a long trial when cognitive fatigue is high. Research shows comprehension rates for key standards can fall below 50 percent even for educated jurors.

What is 'beyond a reasonable doubt' and why is it misunderstood?

It is the standard of proof in criminal cases, meaning the jury must be persuaded to a very high degree before convicting. The phrase is routinely misunderstood in two directions: some jurors interpret it as meaning almost certain (too high), others as meaning the defendant must provide a reason for doubt (too low). Courts in the US often refuse to define it further, despite evidence this increases confusion.

Has plain-language rewriting of jury instructions actually been tested?

Yes. Several US states, including California and Arizona, have revised pattern jury instructions using plain-language principles. Controlled experiments comparing old and revised instructions consistently find improved comprehension scores. The California CALCRIM instructions, introduced in 2005, were developed with input from linguists and psychologists and have been empirically validated.

What are the most comprehension-problematic types of jury instructions?

Research identifies reasonable doubt, specific intent, willful ignorance (deliberate indifference), and insanity as particularly troublesome. Multi-element instructions where jurors must satisfy several criteria are harder than single-criterion ones. Instructions that use a legal term in a way that conflicts with its everyday meaning cause systematic misapplication.

Can giving written copies of instructions to jurors improve comprehension?

Yes, moderately. Providing written copies that jurors can refer to during deliberations improves accuracy compared to oral-only delivery. The improvement is larger when the written copy uses plain language rather than reproducing the original. Video instruction and judge-guided discussion produce the largest gains in controlled studies.

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Instruction element

Comprehension finding

Source

Beyond a reasonable doubt

Correct understanding in 51% of criminal jurors

Reifman, Gusick & Ellsworth (1992)

Specific intent (California)

Correct application in under 50% of scenarios

Kramer & Koenig (1990)

Preponderance of evidence

Confused with reasonable doubt by 30-40% of jurors

Severance, Greene & Loftus (1984)

Deliberate indifference

Correctly applied by approximately 40% of mock jurors

Solan (1999)

Insanity (M'Naghten)

Accurate understanding in roughly 35% of jurors

Ogloff (1991)

Key Takeaways

Jury instructions are drafted for appellate correctness, not lay comprehension, producing reading levels and grammatical structures that exceed what most jurors can decode under oral-only delivery at the end of a long trial.

Empirical research finds correct application of key standards, including beyond a reasonable doubt, specific intent, and deliberate indifference, below 50 percent in multiple studies across jurisdictions.

The causes include nominalisation, passive voice, double negatives, legal-everyday word conflicts, oral-only delivery, and conceptual difficulty that survives grammatical simplification.

Plain-language rewrites, particularly when combined with brief conceptual explanations, written copies, and pre-instruction, produce consistent and substantial comprehension improvements in controlled studies.

Systematic reform has been slow because appellate stability concerns, institutional inertia, and the professional culture of legal drafting all prioritise language correctness over communication effectiveness.

Why do jurors struggle to understand jury instructions?

What is 'beyond a reasonable doubt' and why is it misunderstood?

Has plain-language rewriting of jury instructions actually been tested?

What are the most comprehension-problematic types of jury instructions?

Can giving written copies of instructions to jurors improve comprehension?

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Key Takeaways

Key Takeaways