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A Foundation of Validity

Beginning with the very first notion of a standardized test for admission to law school, validity was a primary focus. In his May 17, 1945 letter to the College Entrance Examination Board (CEEB) suggesting the development of such a test, Frank H. Bowles, Director of Admissions at Columbia University, stated the seven criteria listed below.

Since the inception of the Law School Admission Test (LSAT), the Law School Admission Council (¾«¶«Ó°Òµ) has sought to evaluate and ensure its validity for use in the law school admission process. As predictive validity is an important component in the overall evaluation of test validity, ¾«¶«Ó°Òµ has carried out predictive validity studies, also called LSAT Correlation Studies, since the test was first administered.

Contextual Information for Holistic Evaluation in Law School Admission

The figure below shows the progression of undergraduate yearly grade-point average (GPA) for law school applicants across 4 years of undergraduate study divided into quintiles based on individual Law School Admission Test (LSAT) scores.

The goal of the Law School Admission Council (¾«¶«Ó°Òµ) Skills Analysis Study is to identify the skills that law school faculty consider important for success in required law school courses. If certain tasks are required of all or most law school required courses, the skills involved in those tasks can be inferred to be essential to success in law school.

This study employed a data simulation to evaluate the impact of a strategy to reduce test length by including only high-quality test questions, where quality was defined by a statistical indicator of the degree to which a question distinguishes between more and less able test takers. The impact of this strategy on the rank ordering of simulated test takers according to their total test score was evaluated, as was the predictive validity and classification accuracy of scores based on the shorter tests.

Since the inception of the Law School Admission Test (LSAT), the Law School Admission Council (¾«¶«Ó°Òµ) has sought to evaluate and ensure its validity for use in the law school admission process. As predictive validity is an important component in the overall evaluation of test validity, ¾«¶«Ó°Òµ has carried out annual predictive validity studies, also called LSAT Correlation Studies, since the test was first administered.

The Law School Admission Council (¾«¶«Ó°Òµ) has carried out annual predictive validity studies, also called LSAT Correlation Studies, since the Law School Admission Test (LSAT) was first administered. These studies are geared toward evaluating and ensuring the effectiveness and validity of LSAT scores for use in the law school admission process. In conjunction with these predictive validity studies, ¾«¶«Ó°Òµ also conducts differential validity and differential prediction studies on the LSAT to ensure that the test is fair across gender subgroups.

The Law School Admission Council (¾«¶«Ó°Òµ) has carried out annual predictive validity studies, also called LSAT Correlation Studies, since the Law School Admission Test (LSAT) was first administered. These studies are geared toward evaluating and ensuring the effectiveness and validity of LSAT scores for use in the law school admission process. In conjunction with these predictive validity studies, ¾«¶«Ó°Òµ also conducts differential validity and differential prediction studies on the LSAT to ensure that the test is fair across racial/ethnic subgroups.

Item response theory (IRT) is a mathematical model used to support the development, analysis, and scoring of tests and questionnaires. For example, IRT allows for the description of item (i.e., question) characteristics, such as difficulty, as well as the proficiency level of test takers. Various IRT models are available, and choosing the most appropriate model for a particular test is essential. Since the fit of the test data to the chosen model is never perfect, measuring the fit of the model to the data is imperative.

Item response theory (IRT) is a mathematical model that is often applied in the development and analysis of educational and psychological assessments. Various IRT models exist, and practitioners must choose the model that is most appropriate for their particular assessment. Even when the most appropriate model is applied, the fit of the assessment data to the model is rarely perfect in practice. How serious, then, is model misfit for practical decision-making?

This study was conducted to evaluate the predictive validity of each of the current Law School Admission Test (LSAT) item types as well as the interrelationships among them. The current LSAT consists of three item types: Analytical Reasoning (AR), Logical Reasoning (LR), and Reading Comprehension (RC). Even though the correlation of overall LSAT scaled score with first-year average (FYA) in law school is examined on a regular basis at the Law School Admission Council (¾«¶«Ó°Òµ), the separate correlations for each of these three item types have only rarely been studied.