- In cases where X cannot be manipulated = random assignment is impossible or ethically unacceptable (e.g., political party affiliation, personality, socio-economic status, disease etc.)
- Natural occurring groups are measured and taken as experimental conditions
- ! Causal interpretations should be made with caution !
- The effect could be due to a confounding variable, which just coincides with quasi-X
- Disadvantages of Laboratory (Quasi-)Experiments
- External validity is not guaranteed
Politics
- this is especially hard with politics
- e.g. right-wing people do not support issue X
- might depend on other closely correlated traits
- educational level
- income bracket
- occupation
- upbringing
- etc…
- might depend on other closely correlated traits
Quasi Field Experiments
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A controlled experiment which occurs at places with people going about their normal behavior (e.g. school, parking ramp)
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When trying out behavioral interventions in real-world contexts Field Experiments are often Quasi- Experiments
- A team class gets the intervention, the other team gets no intervention, or an other intervention with a known effect, or gets the same intervention as the experimental group, but later
- Trying out a series of manipulations on the same group or in the same setting (e.g. the same school) over time