4. Experiments Flashcards
What is observation in research?
Registering an empirical phenomenon.
What does manipulation refer to in a study?
Changing a variable in a study.
What is an intervention?
Changing an independent variable.
What is control in research?
Reducing the influence of disturbing factors/variables from influencing the outcome.
What are independent variables?
Variables that are hypothesized to affect the dependent variable.
What are dependent variables?
The variable that changes depending on the changes of the independent variable.
What is the method of difference?
By creating two identical groups, and making an intervention on only one of them, the causal effect of that intervention can be studied.
What defines an experiment?
An observational process characterized by control of the background factors, intervention on the real target variable, and observation of the differences caused by this intervention.
What is a control group?
A contrast class that is not subjected to the intervention, but is similar to the treatment group in all other relevant aspects.
What is a treatment group?
A class that is subjected to the intervention.
What is an observational study?
An observational process characterized by control of the background factors and observation of an outcome, lacking an intervention.
What is a natural experiment?
An observational study where circumstances are organized as if there had been manipulation for intervention and control, but no manipulation is in fact done.
What is a field experiment?
An experiment where there is manipulation for intervention, but where several background variables are not controlled.
What is a laboratory experiment?
An experiment where there is manipulation for intervention and where all or most relevant variables are controlled.
What is a simulation experiment?
A model study where the model is created to mimic an experiment, but where the variables that are intervened on are only represented.
What is internal validity?
An inference in a scientific study is internally valid if the relation between the studied factor and observed effect is indeed true and not confounded by uncontrolled background factors.
What is external validity?
An inference from an experimental system to a different target of interest is externally valid if the conclusion holds for both the system and the target.
What is confirmation bias?
The observation is registered incorrectly due to psychological properties of the observer.
What is selection bias?
A factor influences the selection of the sample or the division into test and control group, which was not aimed to create.
What is the observer effect?
The act of observation changes what is observed.
What is the placebo effect?
The therapeutic effect that an inert substance or treatment has on a patient.
What is repetition in research?
Performing a study again, exactly following the description of the original study.
What is reproduction in research?
Repeating a study and obtaining the same result as in the original study.
What is replication in research?
Performing a variation of a study with the intention to achieve the same result, where some aspect of the study has been changed.
What is constancy in research?
Holding background factors constant between test and control group or between trials in a study.
What is elimination in research?
Removing the influence of a background factor.
What is blinding in research?
Eliminating observer effects through limiting information about the study to participants or observers.
What is single blinding?
Blinding the participants in a study, for instance about whether they are in the test or control group.
What is experimenter blinding?
Blinding the observer in a study, for instance about which subjects are in the test and control group.
What is double blinding?
A study is double blind if both subject blinding and experimenter blinding are implemented.
What is separation in research?
Registering the effect of a background variable.
What is randomization?
Using a random process to divide into test and control.
What is random sampling?
Using a random process to collect a sample from the population.
What are evidential hierarchies?
A ranking of types of evidence based on the processes that produced this evidence.
What is data stratification?
Dividing a sample into categories based on specific properties before randomizing.
What is a known factor?
A factor which you are aware of constitutes a relevant background factor.
What is an unknown factor?
A factor which is a relevant background factor, but which you are unaware of.
