Internal and External Validity

Question 1

What research strategy do you use when examining individual variables?

Answer 1

Descriptive research strategy.

Question 2

What is the descriptive research strategy?

Answer 2

Describes the current state of a variable(s) and does not examine the relationship between variables. (Not comparing between groups)

Question 3

What research strategy do you use when examining the relationship of two variables?

Answer 3

Correlational research strategy.

Question 4

What is the correlational research strategy?

Answer 4

Measure two (or more) variables for every individual/subject in the group and identify correlations between variables. Measures relationship between variables - As one variable changes, does the other variable also change? How does the variable change?
* Positive, negative, curvilinear
No manipulation of any variables

Question 5

What do you use when examining the relationship by comparing scores for each group? (3)

Answer 5

1) Non-experimental research
2) Quasi-experimental
3) Experimental

Question 6

What is non-experimental research? (3)

Answer 6

• One variable has two levels/conditions
• Lacks a control group
• No manipulation

Question 7

What is experimental research?

Answer 7

*Establish cause-and-effect relationships
* Compare 2 or more groups on a dependent variable
* The group is manipulated
* Individuals are randomly assigned to the group
* Has a control group

Question 8

What is quasi-experimental research?

Answer 8

*Similar to experimental
* Has a control group
* But groups cannot be randomly assigned
* In part because of preexisting participant/subject variable
* Does not provide a definitive answer about cause-effect

Question 9

Difference between quasi-experimental vs experimental?

Answer 9

Quasi cannot be randomly assigned.

Question 10

What are the two types of validity and their subgroup?

Answer 10

-Validity of measurement: face validity and construct validity.
-Validity of experiment: Internal validity and external validity

Question 11

What is internal validity?

Answer 11

The extent to which the observed results represent the truth in the population we are studying.

Question 12

What is external validity?

Answer 12

How well the outcome of a research study can be expected to apply to other settings.

Question 13

Validity in nonexperimental research strategies?

Answer 13

• Nonexperimental research allows the researcher to examine the behavior in real-life settings
• Realistic environments offer higher external validity
• Environment is not manipulated or controlled ∴ limited internal validity

Question 14

Validity in Experimental Research Strategies?

Answer 14

• Experimental research allows careful control of the environment
• Conducted in a controlled and constant lab setting ∴ high internal validity
• Experimental research often conducted in unfamiliar
  environments, so harder to generalize beyond the experimental setting ∴ limits external validity

Question 15

Threats to external validity? (3)

Answer 15

1. Generalizing across participants or subjects
2. Generalizing across study features
3. Generalizing across different measures

Question 16

What is generalizing across participants or subjects? (5)

Answer 16

• Selection bias
• Convenience sample
• Volunteer bias
• Participant characteristics
• Cross-species generalization

Question 17

What is generalizing across study features? (3)

Answer 17

• Novelty effects
• Multiple treatment interference
• Experimenter characteristics

Question 18

What is generalizing across different measures? (2)

Answer 18

• Sensitization
• Timing of measurement

Question 19

Threats to internal validity? (2)

Answer 19

1) Obscuring variables
2) Confounding variables

Question 20

What are confounding variables? (4)

Answer 20

An unmeasured variable that influences both the supposed cause and effect
* Assignment bias
* Environmental variables
* Time-related variables
* Observer bias

Question 21

What are obscuring variables?

Answer 21

Variables that can cause null results or misses.
* Ineffective manipulation
* Measurement error
* Excessive variation in data

Question 22

What are the criteria for generalization? (3)

Answer 22

1. Controlled comparison rule:
   * When comparing data between experimental and control groups, the only difference must be the independent variable
2. Sampling rule
   * Adequate sample size to control for random sampling error and unbiased sample so it is representative of the population
3. Operational definitions rule
   * Determines what principles can be generalized
   * Single experiment only allows generalization within specific terms of the operational definition

Question 23

What are exact replicas?

Answer 23

Repeat the experiment, get the same results, and increase confidence in the findings.

Question 24

What are conceptual replications?

Answer 24

The same construct, different experiments/methodology, get consistent results and conclusions get better generalized to entire constructs.