Chapter 10 Ledford Flashcards
time-lagged designs
class of designs well-suited for evaluating and demonstrating accountability in clinical and educational settings
variations of time-lagged designs
- multiple baseline (MB)
- multiple probe (MP)
continuous measurement
planned implementation and data collected during each opportunity or session
intermittent measurement
planned absence of data collection during some opportunities or sessions
concurrent measurement
data collection begins at the same time for all 3+ tiers
when behaviors are functionally independent
introduction of the independent variable to one tier will not bring about change in other untreated tiers of the design
when behaviors are functionally similar
the independent variable is likely to have the same or similar effect on each tier
when behaviors are not functionally independent
behavioral covariation may occur
- begin intervention in first tier, behavior changes in two or more tiers
inconsistent intervention effects
intervention appears to work in one or a few instances but not in others
probe session
several probe trials clustered and presented over a short period of time
probe condition
differs from a baseline condition only in that probe conditions don’t occur for the entire duration of pre-intervention for each tier
two primary variations of MP design
- days variation: data are collected periodically for single session, and over a minimum of 3 days immediately prior to introduction of independent variable
- conditions variation: data are collected for 2 or more consecutive session
MB and MP across behaviors advantages
- permit evaluation and demonstration of intra-participant direct replication
- MP provides a practical means for evaluating programs designed to teach academic and functional skills that are non-reversible once acquired
- MB provides a reasonable method for evaluation programs designed to improve social behaviors difficult to establish and inappropriate to reverse
- condition variation of MP design across behavior provides a paradigm for repeatedly monitoring progress over time
- allow research from across participants where one participant experiences a longer baseline condition
limitations of MB and MP across behaviors
- for each participant, a minimum of 3 behaviors must be identified, each independent of the others yet responsive to the same independent variable
- all behaviors must be monitored repeatedly and concurrently
- prolonged baseline conditions can result in testing threats to internal validity
stimulus conditions
can encompass the dimensions of time, instructional arrangement, activity, setting, control agent, or composition of peer group
Advantages of MB and MP across contexts
- both permit an evaluation and demonstration of participant direct replication
- provide an experimental evaluation of interventions occurring in various contexts for the same participant
limitations of MB and MP across contexts
- challenge of identifying contexts that are functionally independent
- difficulty with measuring behavior across multiple contexts
- increased likelihood of infidelity if a single implementer is used across contexts
- requirement to delay intervention in some contexts
MB and MP designs across participants
- most commonly used variation of MB and MP designs
- well-suited for educational and clinical research when three or more individuals exhibit similar behavior excesses or deficits that require intervention
advantages of MB and MP across participants
- demonstrate some degree of external validity
limitations of MB and MP across participants
- need to identify and recruit thee participants that the same intervention is likely to be effective for the same dependent variable
- increased likelihood of inconsistent effects leading to loss of experimental control
- complexity of simultaneously measuring behaviors for three participants
- ethical and experimental concerns
- lack of intra-participant baseline conditions replication
- potential high risk of testing and maturation threats due to prolonged baseline conditions for some participants
nonconcurrent (delayed) MB designs
- a group of A-B designs with varying amounts of time spent in A condition, beginning data collection in the first tier is not yoked with data collection in other tiers
advantages of nonconcurrent MB design
- practical not experimental
- allows researchers to add participants who exhibit rare behaviors as they become available by implementing a series of A-B designs
limitations of nonconcurrent MB design
although it may have more flexibility than traditional MB or MP designs, it doesn’t and can’t provide a convincing demonstration of experimental control
