Ch 13 Scaling Flashcards
scale
a number of items that combine to form a composite score on a variable
use when a single-item measuring instrument is inadequate
four advantages of scales
improved validity
improved reliability
increased level of measurement
increased efficiency in data handling
5 steps to developing a scale
develop or locate many potential scale items, far more than will appear in the final scale
eliminate items that are redundant, ambiguous, or, for some other reason, inappropriate for the scale
pretest the remaining items for validity, reliability, or other measurement
eliminate items that don’t pass
repeat steps 3 and 4 to reduce the scale to items required
three sources of scale items
researcher’s imagination
group of people (judges) who are knowledgeable in topic
the people who are the focus of the research project
good scale items have several characteristics which are…
validity
range of variation
unidimensionality - measures one variable
5 different scaling formats
likert scales
thurstone scales
semantic differential scales
guttman scales
multidimensional scales
likert scale
consists of a series of statements, with each statement followed by a number of ordered response alternatives
ex responses with strongly agree to strongly disagree
it’s an example of a summated rating scale where a person’s score is determined by summing the number of questions answered in a certain way
nondiscrimination items
those that are responded to in a similar fashion by both people who score high and those who score low
discriminatory power score (DP score) can be used to identify ___
nondiscriminating items
Compute total score for each respondent
Determine quartiles
For each item, classify upper and lower quartiles by response value
Compute weighted totals
Compute weighted means
Subtract lower quartile weighted mean from upper quartile weighted mean
advantages to likert scale
offers respondents a range of choices
data considered to be ordinal which lets us use more powerful statistical procedures
fairly straightforward to construct
disadvantages to likert scale
be careful in interpreting a single score because its a summary of a lot of info
when we summarize data we lose some info
the summary score might hide info abut patterns of variation in responses or about possible multidimensionality of the scale
thurstone scales
constructed so they use equal-appearing intervals, that it is assumed that the distance between any two adjacent points on the scale is the same
Items range from 1 (most unfavorable) to 11, (most favorable). Respondents select the item(s) with which they most agree
Pro to Thurstone scale
Provides interval-level data
People can respond to the items more quickly
Con to Thurstone scale
They are costly and difficult to construct
Semantic differential scales
presents the respondent with a stimulus, such as a person or event, to be rated on a scale between a series of polar opposite adjectives
pros to semantic differential scales
requires only 4 to 8 adjective pairs for each dimension to reach reliabilities of .80 or better
much easier and less time-consuming to construct
adjective pairs are more adaptable
cons to semantic differential scales
generate ordinal data
Guttman scales
items have an inherently progressive nature relating to the intensity of the variable being measured.
There is only one pattern of responses that will yield any given score on the scale.
uses reproducibility
reproducibility
the ability of each individual’s composite score to predict exactly the items agreed and disagreed with
R = 1 - # of errors / (# of items) x (# of subjects)
multidimensional scales
measure variables composed of more than a single dimension.
Locates responses in two, three or N-dimensional space
research for intimate partner violence
scale based on equality, fairness and care
Response bias
is the tendency for people’s answers to questions to be influenced by things other than their true feelings, beliefs, and behaviors.
sources are:
response set
response pattern anxiety
social desirability effect
response set
some people tend to be either yes or no, tending to agree or disagree with statements regardless of their content
response pattern anxiety
some people become anxious if they have to repeat the same response all the time, and they change their response to avoid doing so
social desirability effect
people’s tendency to give socially acceptable, popular answers to present themselves in a good light
5 ways to reduce response bias
designing statements so positive statements are not always an expression of the same attitude
present sensitive issues in a neutral and non-judgmental context
ordering of questions - can be asked in a hierarchical order, beginning with the less sensitive to more sensitive
use an interspersed pattern for the items, where socially acceptable items are interspersed with less acceptable items
funneling - for ex asking questions about their city, then community, then neighbors, then family
scaling is the best example of a strong linkage between practice and research. true or false?
true
human service practitioners use scales to assess specific problems for intervention. true or false?
true
practitioner uses scales to document the progress of intervention. true or false?
true
human service organizations rely on scaling as part of their overall program quality and effectiveness-monitoring process. true or false?
true
rapid assessment instruments (RAI)
Short, easy to administer, easy to complete
Simple, fast scoring procedure
RAIs such as the MAST found superior in assessing severity and nature of problems
Improved reliability of assessment
