| Research method | Important feature(s) | Drawback(s) |
|---|
| Experimental design | Use of independent and dependent variables and random assignment allows researchers to infer cause and effect | Most etiological factors that contribute to psychopathology cannot be studied with experiments (but experiments are often used to study the effects of treatment). |
| Quasi-experiments | Used when it is possible to identify independent and dependent variables, but random assignment of participants to groups is not possible; researchers can still infer cause and effect | Because random assignment isn’t possible, possible confounds are difficult to eliminate. |
| Correlational research | Used when it is not possible to manipulate independent variables such as etiological factors; researchers can examine relationships between variables | Results indicate only related factors, not causal factors. |
| Case studies | Often descriptive, but can use various research methods applied to a single participant | Caution must be exercised in generalizing from the sole participant to others; there are many possible confounding factors. |
| Single-participant experiments | An experiment with one participant (and so random assignment isn’t possible); cause and effect can be inferred | Caution must be exercised in generalizing from the sole participant to others; there are many possible confounding factors. |
| Meta-analysis | A statistical analysis that combines the results of a number of studies that examine the same general question to determine the overall effect | It is difficult to estimate the number of studies that failed to find an effect and thus were not published and not included in the analysis; the studies analyzed are often not of equal quality but their results are nevertheless weighted equally in the analysis. |