Ch 7 Validity

CHAPTER: Validity

Introduction

  • Yun, the newly appointed director of academic and instructional effectiveness at a university, aims to evaluate the university's effectiveness in preparing students for life post-graduation.

  • Existing measures evaluate student learning; however, Yun seeks to assess students' perceptions of university service.

  • A faculty and staff committee identified eight constructs related to college student satisfaction, which must be validated.

Constructs

  • Definition: A construct is an ideational concept used to measure students' satisfaction, not tangible or observable.

  • Yun's test contains both homogeneous (single construct) and heterogeneous dimensions (multiple constructs).

  • Initial constructs include:

    • Quality of education

    • Civility

    • Feelings of belongingness

    • Appreciation of diversity

    • Meta-decision-making

Test Validation

  • The test's validity had not been established; thus, Yun collected feedback from faculty experts after administering it to students.

  • Revisions led to:

    • Reducing constructs from eight to five, combining civility and belongingness into the "culture of respect" construct.

    • Cutting test items from 65 to 28 with some items removed based on expert feedback and validation.

    • Adding items to ensure all constructs were adequately measured (e.g., appreciation of diversity).

What is Validity?

  • Validity: A test's ability to accurately measure what it intends and provide useful results.

  • Importance: Validity is crucial for ensuring that a measure is both accurate and useful as discussed in Lissitz & Sammuelson (2007).

  • Related Concepts:

    • Reliability (consistency of a test).

    • Precision (the reproducibility of a measure).

  • Validation process should ascertain if a test measures the construct accurately before considering its reliability and precision.

Visual Representation of Validity

  • Figures 7-1 to 7-4 depict the relationships between precision, reliability, and validity:

    • High Precision, High Reliability, Low Validity.

    • Low Precision, High Reliability, Low Validity.

    • Low Precision, Low Reliability, High Validity.

Tripartite Model of Validity

  • Validity consists of three components, as identified by Cronbach and Meehl (1955):

    • Content Validity: Examines whether items accurately represent the constructs being measured.

    • Construct Validity: Evaluates how well a test measures the intended constructs and whether the constructs are adequately defined.

    • Criterion Validity: Determines how well a measure predicts outcomes, either concurrent (current behavior) or predictive (future behavior).

Content Validity

  • Evaluates the accuracy of individual items in measuring the construct.

  • The wording of items and response scales significantly contribute to content validity.

  • Example: Items relating directly to college satisfaction should effectively measure relevant sentiments.

  • Experts can evaluate item quality and track the effectiveness of each item using a ratio-based approach.

Evaluating Content Validity

  • Methods include:

    • Expert reviews during construction and after revisions.

    • Confirmatory factor analysis to ascertain that items contribute to the intended constructs.

  • Challenges include the need for a sizeable participant pool for analysis.

Construct Validity

  • Focused on the accuracy and utility of measuring identified constructs.

  • Evaluated through expert consultation to ensure constructs are relevant and adequately represented (theoretical method).

  • Complemented by empirical methods such as exploratory factor analysis to validate identified constructs against data-driven analysis.

Discriminant and Convergent Validity

  • Discriminant Validity: Valid tests should differentiate between different groups relevant to constructs being measured.

  • Convergent Validity: Assesses whether measures correlate with independently established measures of the same construct.

Valid Item Count and Criterion Validity

  • A minimum of three items is recommended per construct for validity, but variability needed can differ.

  • Criterion Validity Types:

    • Concurrent Validity: Validity of measures against established benchmarks for current behaviors.

    • Predictive Validity: Validity of measures in predicting future behaviors based on current data.

Face Validity

  • Measures how valid a test appears to users; impacts willingness of participants to engage honestly.

  • Testing involves user perceptions and modifications based on feedback.

Unitary View of Validity

  • Challenges the tripartite model by emphasizing overall assessment of validity rather than segmenting validity types.

  • Advocates for holistic analysis of empirical and theoretical justifications as ongoing processes in test application.

Steps in Unitary Approach

  1. Test Content Evidence: Ensure items effectively measure constructs.

  2. Response Processes Evidence: Assess how varied test-taker populations interact with items.

  3. Internal Structure Evidence: Correlate scores within and between related tests for construct validation.

  4. Relationships to Other Variables Evidence: Apply theoretical and empirical evaluation of variable relationships.

  5. Consequences of Testing Evidence: Validate that results yield useful insights without misuse.

Conclusion

  • Continuous assessment of validity is crucial for accurate results in both academic and applied measures.

  • The evaluation process enhances the integrity of the testing and consequent interpretations of the results.