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Chapter 7 Measurement and Scale (7.6 Rating Scales (Itemized Rating Scale,…
Chapter 7 Measurement and Scale
7.1 What is measurement
The ability to evaluate the research variable accurately,precisely, and relevantly,an order to meet research objectives.
7.2 Concept
A concept (or construct) is a generalized idea about a class of objects, attributes, occurrences or processes.
Concepts such as age, sex and number of children are relatively concrete properties and they present few problems in definition of measurement.
Concepts such as loyalty, power, job involvement and the likes present greater problems in terms of definition and measurement.
7.3 Operational definition
An operational definition gives meaning to a concept by specifying the activities or operations necessary to measure it.
7.4 Types of scales
Nominal scale
Ordinal scale
Interval scale
Ratio scale
7.5 Criteria of good measurement
Reliability
The ability of a measuring instrument to give accurate and consistent result.
4 different approaches
-Test-retest reliability
-Internal consistency reliability
-Split-half reliability
-Equivalent-form reliability
Every question should have different answers
when cronbach alpha is > 0.7, realibility statistics is acceptable
Validity
the ability of a measuring instrument to measure what is intended to be measured.
(3) basic approaches of validity:
Face / content validity
A professional judgment by an expert on the relevance of the measurement instrument
Criterion-related validity
-The ability of some measure to correlate with other measures of the same construct.
:!: Concurrent Validity
-This is a classification of criterion validity, whereby the new measure correlates with the criterion measure taken at the same time.
:!!: Predictive Validity
-This is another classification of criterion validity where the measurement has the ability to differentiate among individuals with reference to a criterion
Construct validity
-This is the ability of a measure to confirm a network of related hypotheses generated from a theory based on the concepts of the research issues.
Convergent Validity
This is a parameter often used in reference to the degree to which two measures of constructs that theoretically should be related, are in fact related
Discriminant Validity
This means the ability of some measure to have a low correlation with measures of dissimilar concepts
7.6 Rating Scales
Dichotomous Scale
This requires an individual to agree or disagrees with a statement or responds to a single question.
Category Scale
This scale uses multiple items to elicit a single response expanding the response categories provides the respondent more flexibility in the rating task.
Summated Rating Method: Likert ScaleExtremely
-Popular for measuring attitudes because the method is simple to administer.
Individuals generally choose from five alternatives: strongly agree [SA],
agree [A],
uncertain [N],
disagree [D]
strongly disagree [SD]
Semantic Differential Scale
-This is a series of attitude scales.
-This popular attitude-measurement technique consists of identification of a company, product, brand, job or other concept followed by a series of seven-bipolar rating scales.
Numerical Scale
-The numerical scale is similar to the semantic differential scale but the difference is that numerical scale has numbers as response options, rather than ‘semantic space’ to identify response positions.
Graphic Rating Scale
-This scale presents respondents with a graphic continuum.
-The respondents are allowed to choose any point on the continuum to indicate their attitude.
Fixed or Constant Sum Rating Scale
The respondents are given a constant sum of money, script, credits, or points and asked to allocate these to various items. This is an ordinal level technique.
Staple Scale
-Has a number or brief description associated with each response category typically presented vertically, with one adjective appearing at the midpoint of a scale ranging from plus five to minus five.
Itemized Rating Scale
This scale presents respondents with several categories from which the respondent can choose.
Has a number or brief description associated with each response category.
Common forms of itemized rating scales are Likert scale, Semantic Differential scale and Staple scale.