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quasi-experimental design

an experimental design in which assignment of participants to an experimental group or to a control group cannot be made at random for either practical or ethical reasons; this is usually the case in field research. Assignment of participants to conditions is usually based on self-selection (e.g., employees who have chosen to work at a particular plant) or selection by an administrator (e.g., children are assigned to particular classrooms by a superintendent of schools). Such designs introduce a set of assumptions or threats to internal validity that must be acknowledged by the researcher when interpreting study findings. A study using this design is called a quasi-experiment. Examples include studies that investigate the responses of large groups to natural disasters or widespread changes in social policy.

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Psychology term of the day

June 18th 2024

structured observation

structured observation

a systematic method of collecting behavioral data within a controlled environment, often used in research with infants and young children, in which observers measure overt actions and interpersonal processes. In structured observation, researchers (a) select which behaviors are of interest and which are not, (b) clearly define the characteristics of each behavior so that observers all agree on the classification, and (c) note the occurrence and frequency of these targeted behaviors in the situation under analysis. Interaction process analysis and SYMLOG are examples. Structured observation differs from naturalistic observation, which involves observing individuals in their own environments outside of the laboratory.