MORE THAN 40 STATES HAVE ADOPTED PATTERN JURY INSTRUCTIONS, ALSO KNOWN AS STANDARD, MODEL, APPROVED, AND RECOMMENDED JURY INSTRUCTIONS. EACH STANDARDIZED INSTRUCTION STATES A SINGLE PROPOSITION OF LAW IN A SIMPLE AND ACCURATE MANNER. IN COMBINATION, THE STANDARDS FORM A FRAMEWORK FOR THE JUDGE'S CHARGE TO THE JURY. THE USE OF PATTERN JURY INSTRUCTIONS IS MANDATORY IN SEVEN STATES. THE USE OF PATTERN JURY INSTRUCTIONS IS MANDATORY IN SEVEN STATES. MOST STATES INTEND THE PATTERNS AS GUIDELINES. PATTERN JURY INSTRUCTIONS SUPPOSEDLY INCREASE JUROR COMPREHENSION OF THE JUDGE'S CHARGE, REDUCE THE TIME SPENT AT THE TRIAL COURT LEVEL IN PREPARING INSTRUCTIONS, AND RESULT IN FEWER APPEALS AND REVERSALS (ON THE GROUNDS OF IMPROPER INSTRUCTIONS) AT THE APPELLATE LEVEL. IN ILLINOIS, A SURVEY OF APPELLATE COURT CASES DECIDED BETWEEN 1930 AND 1955 FOUND QUESTIONS OF INSTRUCTIONS IN 700 CASES AND REVERSALS IN 266 (38 PERCENT) OF THESE CASES. THE STATE RESPONDED BY PUBLISHING CIVIL JURY INSTRUCTIONS IN 1961 AND CRIMINAL INSTRUCTIONS IN 1968. THE INSTRUCTIONS ARE MANDATORY WHEN APPLIED TO THE FACT OF A CASE. THE VALIDITY OF THE ASSUMPTIONS UNDERLYING THE USE OF PATTERN JURY INSTRUCTIONS WAS EXPLORED BY EXAMINING 2,049 ILLINOIS SUPREME COURT OPINIONS ISSUED FROM 1956 THROUGH 1973. ONLY THREE OF THESE OPINIONS RAISED QUESTIONS OF ERRONEOUS INSTRUCTIONS AS THE SOLE ISSUE ON APPEAL. PATTERN JURY INSTRUCTIONS DID NOT SUBSTANTIALLY AFFECT THE TOTAL NUMBER OF APPEALS IN THE SUPREME COURT. THERE WERE SUBSTANTIAL REDUCTIONS IN THE NUMBER OF APPEALS CITING (AMONG OTHER ISSUES) CHALLENGES TO INSTRUCTIONS, IN BOTH CRIMINAL AND CIVIL CASES, IMMEDIATELY AFTER THE PATTERN CIVIL JURY INSTRUCTIONS WERE PUBLISHED. HOWEVER, IT CANNOT BE DETERMINED CONCLUSIVELY THAT THE REDUCTIONS WERE ATTRIBUTABLE TO THE PATTERN INSTRUCTIONS. PERHAPS JUDGES AND LAWYERS BEGAN TO PAY CLOSER ATTENTION TO INSTRUCTIONS AS A CONSEQUENCE OF THE ATTENTION FOCUSED BY THE PATTERN-DRAFTING COMMITTEE ON THIS ASPECT OF JURY TRIALS. THE ILLINOIS DATA ALSO SHOW THAT REVERSALS FOR ERRONEOUS INSTRUCTIONS ARE RELATIVELY UNCOMMON, AND THAT PATTERN INSTRUCTIONS DO NOT HELP TO REDUCE THE NUMBER OF REVERSALS. ALTHOUGH PATTERN JURY INSTRUCTIONS PROBABLY HAVE CERTAIN BENEFITS AT THE TRIAL LEVEL, THEY APPARENTLY HAVE LITTLE EFFECT IN REDUCING APPELLATE CASELOADS, REVERSALS, AND RETRIALS. BEFORE DRAFTING STANDARD INSTRUCTIONS, STATES SHOULD CONSIDER WHETHER THEY ARE TRULY MORE COST EFFECTIVE THAN TRADITIONAL INSTRUCTIONS. SUPPORTING DATA ARE INCLUDED. REFERENCES ARE FOOTNOTED. (LKM)