The concepts of measurement and the variety of tests are essential to every test administrator. Understanding these fundamental aspects is crucial for effective test design, administration, and interpretation.
What is measurement in simple terms?
Measurement is the process of assigning numbers to the attributes or traits possessed by persons, events, or a set of objects according to specific rules. Educational measurement entails the assignment of numerals to such traits as achievement, aptitude, and performance. It usually answers the question, ‘How much?
Three Main Steps in Measurement
- Identifying and clearly defining the attribute or trait to be measured.
- Determining the procedures or operations by which the attribute will be manifested.
- Establishing a set of procedures or rules for quantifying the attribute or trait.
Scales of Measurement
There are four main categories for Scales of Measurement. They are as follows:
Nominal scales: classify persons or objects into two or more categories. Each person or object can belong to only one category, and members of the same category share a common set of characteristics. Categories are typically assigned numbers for identification purposes. For example, for gender, Male could be represented by 1 and Female by 2.
Ordinal scales: classify and rank subjects based on their degree of a characteristic. Subjects are ordered, such as ranking 5 students by height from 1 to 5, with rank 1 being the shortest and 5 the tallest. While they show which subjects are ranked higher, they may not specify the size of differences between ranks; intervals may vary.
Interval scales: possess the characteristics of both nominal and ordinal scales and, additionally, feature equal intervals. The zero point is arbitrary and does not signify the absence of the characteristic or trait. Values can be added and subtracted from each other, but not multiplied or divided. Examples include Celsius temperature and academic achievement.
Ratio scales: encompass all the characteristics of other types of scales and, additionally, feature a meaningful true zero point. Examples include height, weight, and time. Values on ratio scales can be added, subtracted, multiplied, and divided. For instance, 60 minutes can be considered three times as long as 20 minutes.
TEST
Test: A task or series of tasks used to measure specific traits or attributes in people. In educational settings, tests include paper and pencil instruments with questions for students or pupils to respond to. The responses help the test giver estimate the specific trait being measured and answering the question, ‘How well does the individual perform?’
CONVERGENT TEST: It emphasizes tasks with clear definitions. An example is objective tests featuring multiple options to choose from.
DIVERGENT TEST:It seeks to evaluate creative abilities. Examples include essay-type questions or mathematical equations.
Two interpretations can be given to test scores: norm-referenced and criterion-referenced
Norm-referenced Test: This describes test scores or performance in relation to a reference group, called the norm group. A disadvantage associated with Norm-Referenced tests is that they may not accurately reflect a learner’s performance.
Criterion-referenced Test: This describes test scores or performance in terms of tasks a person with a given score by comparing it to a pre-established standard.
The Concepts of Test Validity and Test Reliability
TEST VALIDITY: Test validity refers to the extent to which a test accurately measures what it is intended to measure. It ensures that the test or measuring instrument aligns with its intended purpose.
The Three Primary Categories of Test Validity
Content Validity: This occurs when a test comprehensively covers all the topics or content areas it is supposed to assess.
Criterion-Related Validity: This type of validity is demonstrated when a test score is used to predict future performance or scores on a related criterion.
Construct Validity: This involves determining the degree to which performance on an assessment accurately reflects an underlying educational or psychological characteristics. It examines whether the test measures the theoretical construct it claims to measure.
Principles Underlying Validity of a Test
There are four guiding principles for test users to determine the validity of assessment results:
- Interpretations of students’ assessment results are valid only if supported by evidence.
- Utilization of assessment results is valid when evidence supports their appropriateness and accuracy.
- Interpretations and uses of assessment results are valid when they align with appropriate educational and social values.
- The validity of interpretations and uses of assessment results relies on their consistency with appropriate values regarding the consequences.
Factors Affecting Validity of Test
- Unclear directions reduce validity if students don’t understand how to respond or the time available.
- Complex reading material can skew validity, measuring unintended skills.
- Ambiguous statements confuse students, diminishing validity.
- Short time limits hinder accurate responses, lowering validity.
- Test items with inappropriate difficulty levels compromise validity.
- Poorly constructed items may unintentionally aid performance, reducing validity.
- Inappropriate test items lower validity by not aligning with desired outcomes.
- Brief tests lack representation, reducing validity.
- Poor item arrangement can affect student performance and lower validity.
- Predictable answer patterns enable guessing, decreasing validity.
- Cheating undermines validity by providing inaccurate results.
- Unreliable scoring, especially for essay tests, diminishes reliability and validity.
Test Reliability
Reliability refers to the extent of consistency in assessment results or scores. It focuses on:
- Consistency across repeated completion of the same tasks on different occasions.
- Consistency across completion of different yet equivalent tasks.
- Consistency across performance markings by multiple raters on the same tasks.
Factors to Consider when Applying Reliability to Test and Assessment
- Reliability pertains to the consistency of assessment outcomes rather than the assessment instrument itself.
- Reliability estimation focuses on a specific aspect of consistency.
- While reliability is a vital aspect, applying it alone does not ensure validity.
- Reliability is predominantly evaluated through statistical measures, such as the reliability coefficient—a correlation coefficient indicating the relationship between scores measuring the same characteristic, typically ranging from 0.0 to 1.0.
Factors Affecting Reliability to a Test
- Test Length: Longer tests tend to yield more reliable scores. For instance, a test comprising 40 items typically offers greater reliability compared to one with only 25 items. Whenever feasible, prioritize using a greater number of items.
- Group Variability: Reliability increases with greater diversity within a group. Conversely, when a group’s abilities are narrowly distributed, reliability decreases. To enhance reliability, design assessments that effectively differentiate between high-performing and less proficient students.
- Item Difficulty: Test items that are excessively difficult or overly simple result in minimal score variation, thereby reducing reliability. Match the difficulty of assessment tasks to the students’ skill levels.
- Scoring Objectivity: Subjectively scored items contribute to lower reliability due to increased variability. Opt for more objective scoring methods whenever possible. For subjectively scored items, employing multiple markers is preferable.
- Time Allocation: Tests with insufficient time allocation, leading to incomplete responses from most students, tend to exhibit lower reliability. Ensure adequate time is allotted for students to complete all items.
- Multiple Marking: Utilizing multiple markers enhances the reliability of assessment results. Relying solely on one grader, particularly for essay tests, term papers, and performances, can diminish reliability. Averaging scores from several markers improves reliability.
- Testing Conditions: Deviations from standardized test regulations and practices by administrators may inaccurately reflect students’ actual performances, reducing reliability. This issue is especially critical in test-retest reliability estimation methods.
STANDARDIZED TEST: A test administered in the same manner to all test takers and graded uniformly. It can be written, oral, or practical, with questions varying in complexity. Non-Standardized test involves giving different tests to different test takers or administering the same test under varying conditions.
Standardized testing facilitates school-to-school comparisons and teacher accountability. Most classroom quizzes and tests are standardized, with all students taking the same test simultaneously and receiving uniform grading from the teacher. The type of test is usually administered to larger groups.
Types of Tests
There are two main types of tests: essay (subjective) and objective tests.
Essay or Subjective Test: This test encompasses higher-order tasks that can vary in difficulty from easy to challenging, and they may be either restricted or extended in scope.
Objective Test: This category includes supply-type questions (such as fill-in-the-blank and short answers) as well as selection-type questions (including matching, multiple-choice, and true/false formats). These tests typically involve the use of a key and distractors and may present varying levels of difficulty.
Keep following gheducate.com for more credible information and updates. Kindly share to others
