PS280 Study Guide - Midterm Guide: Random Assignment, Tads, Experiment
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Research Methods:
-primary goals of clinical research: (1) description of clinical phenomena: specification and
classification of an event, (2) prediction of behaviour
-knowledge ascertained by observation and experimentation, critically tested, systemized, and brought
under general principles (experimental or non-experimental)
-in a true experiment, participants are randomly assigned to experimental and control groups
-placebo effect :plaecbo participants expect to get better / report improvement to please experimenter
-double-blind procedure: to ensure expecations do not influence outcome of study
-internal validity: degree to which changes in DV are result of manipulation of IV
- Treatment for Adolescents with Depression Study (TADS) showed CBT and Prozac combined were
most effective at reducing depression + increasing protective factors
-controlled experiments allow for causation but (1) difficult to control for so many factors, (2) ethical
dilemmas regarding random assignment (ex early AIDS studies), (3) rigour limits generalizability
-quasi-experimental study: participants in experimental group are not randomly assigned but selected
on the basis of certain characteristics + there is no manipulation of IV
-confound: 2 or more variables exert their influence at the same time, making it impossible to
accurately establish the causal role of either variable (DSM-5 based largely on quasi-experiments)
-assignment on basis of personal characteristics limits cause-and-effect inferences that are possible
Non-experimental methods:
(1) correlational: non-invasive, A caused B/B caused A/C caused A and B
-can identify direction of relationship through longituinal studies
(2) case study: description of past and current functioning of a single individual, goal is description
-useful in description of rare disorders + to generate hypotheses concerning etiology/treatment