Research Studies: detect cause-and-effect relationships between variables

1. Observational Studies

1.1. unit

1.2. participant

1.3. types

1.3.1. retrospective study

1.3.2. prospective study

1.3.3. case-control study

2. Experiments: measure the effect of manipulated conditions

2.1. Randomized experiments

2.1.1. treatments

2.1.2. randomization

2.1.2.1. type of treatment

2.1.2.2. order of treatments

2.1.3. control group

2.1.4. placebos

2.1.4.1. placebo effect

2.1.5. blinding

2.1.6. blinding

2.1.6.1. double-blind

2.1.6.2. single-blind

2.1.6.3. double dummy

2.1.7. designs

2.1.7.1. matched-pair designs

2.1.7.2. block design

2.1.7.2.1. blocks

2.1.7.2.2. randomized block design

2.1.7.3. repeated-measures designs

2.1.7.4. completely randomized design

2.2. experimental unit

2.3. subjects

2.3.1. volunteers

3. Variables

3.1. explanatory variable

3.2. response variable

3.3. outcome variable

3.4. dependent variable

3.5. independent variable

3.6. confounding variable

3.7. lurking variable

4. Difficulties and Disasters

4.1. confounding variables

4.2. interacting variables

4.3. confounding variables

4.3.1. Rule for Concluding Cause and Effect

4.4. experimenter effects

4.4.1. Hawthorne effect

4.5. ecological validity