Experiments, Randomized experiments, Treatments
Types of Observational Studies, Retrospective, Prospective, Case-Control
Advantages of Case-Control Studies, Efficiency, Reducing Potential Confounding Variables
Randomization:The Crucial Element, Randomizing the Type of Treatment, Randomizing the Order of Treatments
Control Groups, Placebos, and Blinding, Control Groups, Placebos, Blinding, Double Dummy
Pairing and Blocking, Matched-Pair Designs, Block Designs
Design Terminology and Examples, Completely Randomized Design, Matched-Pair Design, Randomized Block Design
Confounding variables and the implication of causation in observational studies, Cause and effect relationships can be inferred from randomized experiments but not from observational studies
Extending results inappropriately, Available data can be used to make inferences about a much larger group if the data can be considered to be representative with regard to the question of interest
Hawthorne and experimenter effects, The hawthorne effect is when participants in an experiment respond differently than they otherwise would, just because they are in the experiment, Experimenter effects are when the experimenter has bias results., These effects include recording the data erroneously to match the desired outcome, treating subjects differently on the basis of which condition they are receiving, and subtly making the subjects aware of the desired outcome.
Ecological validity and generallizability, Ecological validity is when the variables have been removed from their natural setting and are measured in the laboratory or in some other artificial setting.
Using the past as a source of data, If possible, retrospective studies should use authoritative sources such as medical records rather than relying on memory.