PSYCHOTHERAPY ENGAGERS VERSUS NON-ENGAGERS

Definitions of dropout based on number of sessions can potentially misclassify
clients who have achieved sufficient clinical change, and definitions of dropout based on
therapist judgment can vary depending on the therapists’ ideas about what counts as a
dropout. Though definitions of dropout using a cut-off number of sessions combined with
therapist judgment decrease the likelihood of misclassifying clients as dropouts, they still
have the potential to misclassify clients who actually have made sufficient clinical
improvement (they may take a standardized outcome measure and score in the clinically
healthy range—therapist judgment can be subjective and could differ from the results of a
standardized outcome measure).
Swift, Callahan, and Levine (2009) proposed a definition of dropout based on
clinically significant change and/or reliable change to address the misclassification
problem. They defined clinically significant change as having been attained when “(a) the
client obtains a score within the nonclinical range on a standardized outcome measure
and (b) the change in score reflects reliable improvement” (p. 330). Reliable change is a
less stringent operationalization that can be useful since few clients obtain clinically
significant change through therapy (Swift et al.). In their study, Swift et al. use a cut-off
score of 63 on the Outcome Questionnaire 45.2 (OQ-45.2; Lambert et al., 1996; Lambert,
Okiishi, Finch, & Johnson, 1998) as the indicator for clinically significant change and a
change of 14 points on the OQ-45.2 as the indicator for reliable change. These
operationalizations were based on the OQ-45.2 manual (Swift et al., 2009).
Although Swift et al. (2009) made a convincing argument for using clinically
significant change and reliable change to define dropout, clients can be misclassified
under their system. We can use the example of a client who scored in the nonclinical
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