a.) Laboratory experiments.


Strengths:

-You are able to control the variables e.g. make all of them constant except one.
-Controlling variable also helps to identify the nature of correlation: causative or coincidental.
-The results are easy to be quantified - represented in the form of numbers.
-Laboratory experiments are easier to replicate that field experiments.

Limitations:

-Difficult to apply such experiments to people as they may behave artificially, therefore results may be unreliable
-Experimental effect


b) Field experiments.


Strengths:

-This type of experiment allows to avoid artificial behaviour
-Easier to apply to people than laboratory experiment

Limitations:

-It is difficult to control the variables because such experiment is conducted in a usual social situation.
-The Hawthorne effect: if people are aware of being a part of experiment, they may act differently, therefore the results may be unreliable.
-Experimenter bias - the experimenter may have an unintended effect on those who are being studied and thus produce unreliable results.
-Ethical questions - should people be aware of being a subject of an experiment? Do they have to agree to do it?


c.) Comparative method.

Strengths:

-That method allows to investigate the causes of the particular events.
- Influence of variables can be estimated

Limitations:
Difficult to adjust the research to cultural differences e.g. difficult to compare things which may not be really alike.