PAAS-Week 4- Introduction to study design, measurement variables. Flashcards
What are features of a good design?
Controls (need to see the causal relationship)
Randomisation
Blinding
A theoretical framework
What are some different types of experimental studies?
True experiments
Quasi-experiments
And natural experiments
What are True experiments?
True experiments usually have tight controls
They can be somewhat artificial because they abstract away from the real world (not in real life settings- so it’s hard to see if the findings from the experiment actually generalize)
This means they lack ecological validity
Ecological validity refers to the ability to generalize the results from an experiment to the real world
Just because something is true in the lab, doesn’t necessarily mean it’ll be true in the real world
But experiments provide the most rigorous methodology for investigating causal relationships.
Experiments can be difficult to perform from a logistical point of view, because randomisation can be difficult, and sometimes manipulating IVs directly can be difficult or impossible
Quasi-experiments are similar to true experiments except for participant randomization (do not use randomization)
This makes them useful in situations were randomisation isn’t possible
What are natural experiments?
Natural experiments are studies where randomisation and manipulation occur through natural or
socio-political processes (studies good when you can’t manipulate the variable- its naturally occurring)
What is an in-between subject design?
Every participant experiences only one condition, and you compare group differences between participants in various conditions.
What is a within subject design?
A within-subject design is a type of experimental design in which all participants are exposed to every treatment or condition.
What are mixed designs?
Mixed designs have both within-subject and between-subject manipulation
What are the advantages/ disadvantages of within subject design?
Disadvantage- boredom effect/ order effect- might perform worse in second condition because they are tired.
Advantage- Can be easier to detect differences between conditions.
What are longitudinal designs?
Involves repeated measurements of the same characteristics from the same participants at
multiple different points in time
Logistically very difficult to do and can be expensive. Some can run for years or even decades
Very useful for seeing how things change overtime. Particularly useful for studying e.g.,
developmental processes
Because they can run for so long there can be issues with missing data
What is construct validity?
Whether the tool you are using to measure something is actually measuring what you want it to measure
What is external validity?
We want to be able to generalize the findings from our studies beyond the particular people that took part in our study
And we want to be able to generalize the findings from our studies beyond the exact experimental tasks and setup used in our study
A study has external validity if it can be generalized to the population of people with relevant
characteristics
Studies in psychology are normally WEIRD- what does this stand for?
Western
Educated
Industrialised
Rich
Democratic
What is reliability?
Reliability is about the consistency of a measure
A measure is reliable if it produces the same results each time it’s used on the same participant
What are the different levels of measurements?
Nominal/categorical
Ordinal
Interval
Ratio
