DEFINITIONS

 

 

·        Reliability

·        Validity

·        Levels of measurement

·        Defining measurement

·        Measurement theories

·        Standardized measurement

·        Construct

·        Tests vs scales

·        Type of tests

·        Cognitive test

·        Psychomotor test

·        Affective test

·        Norm-referenced & Criterion-referenced testing

 


 

RELIABILITY

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Reliability refers to the accuracy (consistency) and stability of measurement by a test.  (APA, 1966, p.182)
  •  

Reliability refers to the degree to which results of testing are attributable to systematic sources of variance.  (APA, AERA, & NCME, 1974, p.48)

  •  

Reliability is the degree to which the scores are consistent, dependable, or repeatable, that is, the degree to which they are free of errors of measurement (AERA, APA, & NCME, 1985, p.93)  

 

Types of reliability:

·        Stability

·        Equivalence

·        Stability & Equivalence

·        Internal consistency

·        Decision consistency

 


VALIDITY

 

  • ·

Validity refers to the appropriateness of inferences from test scores or other forms of assessment and validation refers to the determination of appropriateness for all the interpretations made of a test score: descriptive, explicative, and predictive.
(APA, AERA, & NCME, 1974, p.25).

 

  • ·

Validity is defined as the degree to which a certain inference from a test is appropriate or meaningful and validation as the process of the investigation by which the degree of validity of a proposed test interpretation can be evaluated. 
(AERA, APA, & NCME, 1985, p.94).

 

 « Validity is inferred not measured »

 

Types of validity

·        Criterion-related validity

·        Content validity

·        Construct validity

 


LEVELS OF MEASUREMENT

 

Stevens (1946) four levels of measurement

·        Nominal scales

·        Ordinal scales

·        Interval scales

·        Ratio scales

 

Other scales

·        Stevens (1958) logarithm interval scale

·        Torgerson (1958, p.19) two ordinal scales

·        Coombs (1950) scale

 


 

 

MEASUREMENT & MEASUREMENT THEORY

 

"Measurement is the assignment of numerals to objects or events according to rules" (Stevens, 1946). 

"Measurement is the assignment of numerals, in accordance with rules, for quantitative representation of characteristics of individuals" (Hulin, Drasgow, & Parsons, 1983).

 

This definition rules out the use of nominal and ordinal scales

 

Important concepts
1. Scaling
2. Classification
3. Classification of characteristics or attribute

 

Direct versus Indirect measurement
Physical versus Psychological attributes

 

"Measurement theories consist of sets of rules by which one establishes unique correspondences between numerals and amounts or magnitudes of individuals' or objects' characteristics" (Hulin, Drasgow, & Parsons, 1983). 

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