Developing and Testing Self-Report Scales & Descriptive Statistics in nursing
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Chapter 15
Developing and Testing Self-Report Scales
*
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
Tell whether the following statement is true or false:
Scale development begins with a sound conceptualization of the construct (the latent variable) to be measured, excluding its dimensionality.
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
False
Scale development begins with a sound conceptualization of the construct (the latent variable) to be measured, including its dimensionality.
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Conceptualizing the Construct
Scale development begins with a sound conceptualization of the construct (the latent trait) to be measured, including its dimensionality.
Unobservable latent trait
Unidimensional
*
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Type of Scale
Scale selection is done before items can be generated.
Two broad categories of multi-item reflective scales
Traditional summated rating (Likert)
Latent trait
*
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Generating Item Pool
Sources
Existing instruments
Research literature
Concept analyses
In-depth studies
Clinical observations
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Decisions about Item Features
Number of items
Response items
Positive and negative stems
Item intensity
Item time frames
*
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Number of Items
Domain sampling model: homogeneous set of items from a hypothetical universe of items
Goal is to provide appropriate redundancy so idiosyncrasies can be cancelled out.
Recommends starting with 3 to 4 times as many items as you will have in your final scale
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Response Options
Scale items contain:
A stem
Response options
For example, strongly disagree, disagree, agree, strongly agree
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Positive and Negative Stems
The objective was to include items that would minimize the possibility of an acquiescence response set—the tendency to agree with statements regardless of their content.
Many experts currently advise again including negative and positive items on a scale.
*
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Item Intensity
The intensity of the statements (stems) should be similar and fairly strongly worded.
Statements should not be so extremely worded as to result in universal rejection.
*
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Item Time Frames
A time frame should not emerge as a consequence of item development.
It should be decided upon in advance, based on the conceptual understanding of the construct and the needs for which the scale is being constructed.
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Wording the Items—Readability
Clarity
Jargon
Length
Double negatives
Double-barreled items
*
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
Once content validity has been established at a satisfactory level, the scale must be administered to a development sample. What is the typical number of respondents who are representative of the target population?
100
150
250
300
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
D
Once content validity has been established at a satisfactory level, the scale must be administered to a development sample—typically 300 or more respondents who are representative of the target population.
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Content Validity
Satisfactory level
Development sample
300 or more respondents representative of target population
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Field Testing the Instrument
Developing the sampling plan
Developing a data collection plan
Preparing for data collection
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
Tell whether the following statement is true or false:
Exploratory factor analysis is used to reduce a small set of variables into a larger set of underlying dimensions, called factors.
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
False
Exploratory factor analysis is used to reduce a large set of variables into a smaller set of underlying dimensions, called factors.
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Analysis of Scale Development Data
Basic item analysis
Inter-item correlation
Item–scale correlations
Exploratory factor analysis (EFA)
Factor extraction
Principal components analysis (PCA)
Factor rotation—orthogonal or oblique
*
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Illustration of Factor Rotation
*
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Scale Refinement and Validation
Revising the scale
Scoring the scale
Conducting a validation study
Confirmatory factor analysis
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Confirmatory Factor Analysis
CFA is a second study often undertaken to validate the scale.
A subset of sophisticated statistical techniques (structural equation modeling)
Involves tests of a measurement model
Stipulates the hypothesized relationship between latent traits and manifest variables (items)
*
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Interpretability of Scale Scores
Interpretability: the degree to which one can assign qualitative meaning
Percentile
Standard scores
Norms
Cutoff points
Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins
Critiquing Scale Development Studies
Methods used
Whether the evidence regarding the scale’s psychometric adequacy is sufficiently sound
See Box 15.1
Looking for a Similar Assignment? Order now and Get 10% Discount! Use Coupon Code “Newclient”
