SWK 420 Chapter Notes - Chapter 4: Odometer, Dependent And Independent Variables, Inter-Rater Reliability
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SWK 420 Chapter 4
• Single-system research designs (SSRDs) provide practitioners with immediate,
inexpensive, and practical feedback on whether their clients are improving.
• SSRD typically focuses on an individual client and his or her situation.
• SSRD can be used to evaluate the progress being made by a community, an organization,
a family, or even a couple receiving marital counseling.
• The choice of a target behavior or outcome variable must allow for frequent or
continuous assessment the chief characteristic of all SSRDs.
The Origin of Single-System Research Designs
• Case examples are sometimes called case vignettes.
• B. F. Skinner and other practitioners of behavior modification are credited for the
emergence of single-system research designs in the 1960’s and 1970’s.
• SSRDs use objective measures to document that change has occurred.
Anxiety Check 4.1:
What is the difference between an objective and subjective assessment?
A subjective assessment reflects personal values or perspectives. I may think, for instance
that I can tell when a person is lying. An objective assessment is when there is documentable
evidence. For example, a roommate borrows a friend’s car to go to the grocery store but the car’s
odometer reveals that he actually travelled 50 miles instead of 3 to the nearest supermarket. The
odometer is objective evidence of the distance travelled.
A Closer Look at the SSRD
• Target behavior is the dependent variable.
• Although it is possible to use statistical procedures to check for statistically significant
differences in improvement, this is not a requirement or a necessity for most single-
system research designs.
• The pre-intervention data create the baseline and allow for comparisons to be made
during treatment and possibly later in a follow-up period
• Retrospective baselines are memory-based estimates of the severity of a problem or in
some instances, they could be based on actual data that already exist, such as grades on a
mid-term report or absences from school on a report card.
• Prospective baselines or concurrent baselines are measurements of the problem that are
usually begun at or immediately after an initial assessment and extend into the future.
• The measurement of a target behavior prior to beginning intervention (the baseline)
second key characteristic of SSRDs.
Steps In Starting An SSRD:
Step 1: Define the problem and choose a behavior to monitor.
• When choosing a target behavior, keep the following in mind:
o Target behaviors should come from the client.
o The best place to start is with the problem the client has identified as being most
SWK 420 Chapter 4
• Use the following criteria to prioritize the problem mentioned by clients:
o Problems that are the most concern to the client or court
o Problems that have the most negative consequences for the client, the client’s
significant others, or society.
o Problems that have a high probability of being corrected quickly and providing an
experience of success that may lead to continuing work
o Problems that require handling before other problems can be addressed.
Step 2: Select a tool that allows you to identify a concrete and observable behavior
• Target behavior should be so well defined that others would have little difficulty in
observing or recording them.
• The easiest problems to measure are those that are easily recognized by others and
Step 3: Measure a Behavior
• Three ways to measure a behavior
2. Duration or length of time
3. Magnitude or intensity
Step 4: Define the intervention
Step 5: Choose the SSRD to use
• On the vertical line (y-axis), plot the number of times (frequency) the target behavior
• The horizontal line (x-axis) is used to portray the behavior as it occurs over time.
• The baseline period is that it should contain at least three observations
• Choose a behavior that is fairly dependable in its occurrence
• In some instances, clients can keep logs or self-report on the occurrence of the target
behavior. In other situations, someone else will need to monitor the behavior. These
decisions are individually determined by the practitioner from knowledge of the client’s
abilities and situation.
Types of SSRD Designs
The Case Study or B Design
• Case studies are detailed descriptions of an individual, client, family, group, community,
or other “units.”
• Case studies lack baseline measures and use anecdotal information rather than systematic
and objective assessment of the target behavior.
• No attempt is made to compare the behavior at the end of the intervention with its
baseline (because there was none.)
• The case study has a number of serious limitations:
o Lack of systematic observation and standardization of assessment
o No baseline measures
o Little control of the treatment variable (the intervention may involve several