Potential Uses of Single- System Designs n Assess and monitor change - PDF document

Potential Uses of Single- System Designs n Assess and monitor change Single Subject Designs n Evaluate whether change has occurred n Determine whether change in Lecture 6 intervention is needed n Determine whether intervention caused observed change n Compare relative effectiveness of interventions Key Characteristics of Single-System Designs Phases n Different phases n Period of time during which distinctive evaluation activity occurs n Baseline n Intervention n “ A ” represents baseline phases n Follow-up n “ B ” through “ Z ” represent n Comparison of baseline and intervention phases intervention phases n “ B ” or “ BC ” etc. represent multiple interventions n Change intervention, as needed n “ B 1 , ” “ B 2 , ” “ B 3 , ” etc. represent n Change design, as needed changes in intervention intensity Phases (cont ’ d) Baseline Phase n Length of phases n Period of time during which no formal intervention is implemented n Long enough to obtain a clear, representative, and stable picture of n Usually first implemented prior to target intervention n Adjacent phases should be equal length, ideally n Comparison of nonadjacent phases should be done with care, if at all 1

Baseline Purposes of Baseline n Period of time during which no n Provides a basis of comparison to formal intervention is implemented determine change (i.e., evaluation) n Usually first implemented prior to n Assessment intervention n Determine extent of the problem n Analogous to a control group n Determine cause(s) of problem Types of Baselines Length of Baselines n Concurrent/prospective n Long enough for assessment and evaluation n Reconstructed/retrospective n Clear, representative, and predictable n Best for specific events picture of target n Should be recent if based on memories n Baseline/intervention comparison n Combined retrospective and assumes that if the intervention had prospective not occurred, the baseline pattern would have continued unchanged n Minimum of 3 observations, ideal of 7 to 10 or more observations Baseline: Predictable and Baseline: Predictable and Not Variable Variable 100 100 90 90 80 80 70 70 Depression Depression 60 60 50 50 40 40 30 30 20 20 10 10 0 0 1 2 3 4 1 2 3 4 Week Week 2

Baseline: Not Predictable When are Baselines and Variable Unnecessary? n Prospective baseline unwarranted in 100 90 some crises situations 80 70 n Prospective baseline unnecessary Depression 60 when no history of desired behavior 50 40 having occurred 30 20 10 0 1 2 3 4 Week Intervention Phase Follow-up Phase n Period of time during which formal, n Period of time after completion of planned, systematic practitioner an intervention during which actions designed to change a target maintenance of change is monitored take place and, perhaps, reinforced n One or a combination of interventions implemented n Should be related clearly to goals n Should be specified clearly Comparison of Baseline and Change Intervention, As Intervention Phases Needed n Used to determine change n Interventions may be continued, added, removed, replaced, or n Assumption is that if the changed in intensity intervention had not occurred, the baseline pattern would have n Change in response to deterioration continued unchanged of target n Change in response to insufficient improvement in target n Change in response to attainment of goal 3

A-B Design A-B Design (2 Outcomes) 40 50 40 30 Outcome Depression 30 20 20 A B A B 10 10 0 0 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 Week Week A-B-A Design A-B-A Design 40 40 30 30 Depression Depression 20 20 A B A A B A 10 10 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 1 2 3 4 5 6 7 8 9 10 11 12 13 Week Week Marital Conflict and Components of a Good Depression (B-only Design) Recording Plan n Select a measurement method 5 n Decide who should collect data 4 3 Rating n Decide when and where to collect 2 data 1 n Decide how often to collect data 0 n Decide how many targets to record 1 2 3 4 5 6 7 8 9 Weeks n Standardize recording procedures Marital Conflict Depression 4

Decide Who Should Collect Methods for Observing Data Behavior n Advantages and disadvantages with n Self-monitoring different sources n Self observation n Client n Overt or covert behavior n Practitioner n Direct observation n Independent evaluator (e.g., n Outside observer supervisor, colleagues) n Limited to overt behavior n Relevant others (e.g., spouse, parent) Charting Conventions Visual Analysis n Outcome on vertical axis n Change in level n Time on horizontal axis n Change in trend n Phases separated by vertical line n Nature of change n Don ’ t connect lines across phases n Improvement n Use care in plotting missing data n “ A ” designates baseline phase, B…Z designate n Deterioration intervention phase n No change n 2 or 3 outcomes can be plotted on the same chart to examine covariation Difference in Level: Difference in Level: Deterioration Improvement 100 100 90 90 80 80 70 70 Depression Depression 60 60 50 50 40 40 30 30 20 20 10 10 0 0 1 2 3 4 5 6 1 2 3 4 5 6 Week Week 5

Difference in Trend: Difference in Trend: Improvement Deterioration 100 100 90 90 80 80 70 70 Depression Depression 60 60 50 50 40 40 30 30 20 20 10 10 0 0 1 2 3 4 5 6 1 2 3 4 5 6 Week Week Difference in Level & No Difference in Trend Trend: Deterioration 100 100 90 90 80 80 70 70 Depression Depression 60 60 50 50 40 40 30 30 20 20 10 10 0 0 1 2 3 4 5 6 1 2 3 4 5 6 Week Week Potential Problems with Visual Analysis Daily Frequency of Crying n Sometimes change is ambiguous 6 5 Crying Episodes 4 3 2 1 0 1 4 7 0 3 6 9 2 5 8 1 4 7 0 3 6 9 1 1 1 1 2 2 2 3 3 3 4 4 4 4 Day 6

Daily Frequency of Crying With Median Lines Trend n Average rate of increase or 6 decrease over time 5 Crying Episodes 4 n Measures of central tendency are 3 inappropriate for data exhibiting a 2 trend 1 0 0 3 6 9 2 5 8 1 4 7 0 3 6 9 1 4 7 1 1 1 1 2 2 2 3 3 3 4 4 4 4 Day Repeated Measurement Using Individualized Rating Scale Trend with Mean Lines (IRS) 10 n Also known as a “ target complaint 8 Crying Episodes scale, ” a “ self-anchored scale, ” 6 and an “ individual problem rating 4 scale ” 2 n Tailor-made for each client 0 1 2 3 4 5 6 7 8 Day IRS Example Advantages of IRS ’ s n Can be completed by clients, Intensity of anxiety today practitioners, relevant others, or (1) Little or no anxiety independent evaluators (2) Some anxiety n Tailored to individual clients (3) Moderate anxiety n Easy to administer and score, and (4) Strong anxiety so can be used frequently (5) Intense anxiety 7

Advantages of IRS ’ s Repeated Measurement Using (cont ’ d) Logs n Can be used with most clients n Also known as “ client annotated records ” and “ critical incident recording ” n Can be used to measure intensity of n Organized journal of events relevant to targets targets, and the client ’ s perceptions of n Can be used to measure thoughts the circumstances under which these and feelings occur n Evidence of good reliability, n Used mostly by clients, but can be used by practitioners and significant others validity, and sensitivity to change Marital Conflict and Depression (2 outcomes) Depression Level 50 5 45 40 4 Depression Level 35 30 3 Rating 25 2 20 15 1 Baseline Treatment 10 5 0 0 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 Weeks Weeks Marital Conflict Depression Child ’ s Problems Rated by Mother and Father Internal Validity A claim to good external validity is how 50 representative is the study ’ s Child's Problems 40 participants. 30 20 Few human services projects and program evaluation use random 10 sampling of the population and use 0 1 2 3 4 5 6 7 8 9 convenience of some kind. Weeks Mother Father 8

Replication n The process of duplicating an experiment-in which the same hypotheses, variables, sampling procedures, testing instruments, and techniques are used with a different sample of the same population. (Barker, 1999, p. 409) (Case confidence) 9