Educational Test Quality: Reliability, Practicality & Types

Posted on Mar 28, 2025 in Naval Architecture

Educational Test Quality

Test Reliability

Defining Reliability

Reliability refers to the consistency with which a test measures abilities. This implies, for example, that the same score should ideally be obtained if the test is taken on one particular day or on the next. Sources of unreliability may be found in some features of the test itself or in the methods of scoring it.

In a research context, reliability also means the extent to which an independent researcher, analyzing the same data, would reach the same conclusions, and a replication of the study would yield similar results.

  • Internal reliability refers to the consistency of the results obtained within a single piece of research.
  • External reliability refers to the extent to which independent researchers can reproduce a study and obtain results similar to those obtained in the original study.

Enhancing Test Reliability

Intrinsic Reliability (For Students)

How to make tests more reliable for students:

  • Take enough samples of behaviour: It has been demonstrated that adding more items generally makes a test more reliable.
  • Do not allow candidates too much freedom: Use more concrete themes or structured tasks.
  • Write unambiguous items: Candidates should not encounter items whose meaning is unclear or which have acceptable answers not anticipated by the test writer.
  • Provide clear and explicit instructions.
  • Ensure tests are well laid out and perfectly legible: Avoid issues like excessive text that is poorly reproduced.
  • Ensure candidates are familiar with format and testing techniques: Provide sample tests and practice materials.
  • Provide uniform and non-distracting conditions of administration: Ensure consistency in timing, acoustic conditions, and minimize distracting sounds.
Extrinsic Reliability (Scorer Reliability)

How to make scoring more reliable:

  • Use items that permit scoring which is as objective as possible.
  • Make comparisons between candidates as direct as possible: For example, through careful choice of items or guided exercises.
  • Provide a detailed scoring key: Specify acceptable answers and guidelines for partially correct responses. Consider holistic scoring versus analytic scoring approaches.
  • Train scorers: This is especially important where scoring is subjective. Monitor scoring patterns (e.g., using Rasch analysis).
  • Agree on acceptable responses and appropriate scores at the outset of scoring: Review sample scripts (like compositions) to anticipate unexpected but valid answers.
  • Identify candidates by number, not name, gender, or nationality, to reduce bias.
  • Employ multiple, independent scoring: As a general rule, where testing is subjective, all scripts should be scored by at least two independent scorers.

Test Practicality

A test should be practical, meaning it is appropriate for the available resources. It should be reasonably easy and cost-effective to construct, administer, score, and interpret.

Practicality is important because tests are measures used for:

  • The evaluation of student performance for comparison and selection purposes.
  • The evaluation of teaching effectiveness, allowing necessary adjustments to help specific groups or individuals benefit more. Tests help teachers evaluate the effectiveness of the syllabus, methods, and materials used.

Purposes of Educational Testing

Proficiency Tests

These tests are designed to measure a person’s ability in a language, regardless of any specific training they may have had. Proficiency means having sufficient command of the language for a particular purpose. Proficiency tests are based on a specification of what candidates need to be able to do in the language, not on the content of previous courses.

Achievement Tests

These tests are directly related to a language course and aim to establish how successfully individual students or groups have achieved the course objectives.

  • Final achievement tests are administered at the end of a course of study. They may be created by ministries of education, official examining boards, or teaching institutions.
  • Progress achievement tests are intended to measure the progress students are making during a course and should be related to specific learning objectives covered.

Diagnostic Tests

These tests are used to identify students’ strengths and weaknesses – what they know and what they do not. They are typically very detailed and provide a lot of specific information to guide future learning or teaching.

Placement Tests

These tests are intended to provide information that helps place students at the stage or part of a teaching program most appropriate to their current abilities. Placement tests aim to predict the most suitable starting point for students, although their predictive power for overall future ability may vary.