PSYCH 115 Lecture Notes - Lecture 21: Clinical Trial, Internal Validity, Psych
Document Summary
Surveys large groups of people to get a picture of an entire population. Examines incidence, prevalence, and course of disorders. Involves manipulating a variable (i. e. , introducing or withdrawing something in a controlled way) Clinical trial: experiment designed to evaluate the effectiveness of a treatment. Often matched to demographics of experimental group. Placebo: some participants are given an inactive treatment (e. g. , sugar pill), Double-blind: participants and assessors are unaware of what kind of but participants don"t know which treatment they are getting treatment participants are getting. Placebo effect: something changes simply because the participant expects the change to occur (e. g. , expecting to feel better when taking an inactive pill) Manipulate timing and nature of experimental conditions. Frequent repeated measurement of outcomes is critical. Permits conclusions about changes over time relative to the introduction and withdrawal of certain variables. First establish a baseline, then introduce treatment. Then, stop treatment to see if behavior/symptoms return to the way they were before treatment.
