Internal validity refers to the certainty that experimental interventions did indeed cause the changes observed in the study group; also the control over confounding factors which tend to invalidate the results of an experiment .
Other definition:
Internal validity refers to the extent to which an intended manipulation of a variable, rather than extraneous influences, accounts for observed results, changes, or Group differences.
Other /More definition:
internal validity refers to extent to which the results of a study can be attributed to the independent variable after confounding alternative explanations have been ruled out.

Related Articles

Confound at psychology-glossary.com■■■■■■■■■■
confound refers to any factor occurring in a study that makes the results uninterpretable because its . . . Read More
Experimenter bias at psychology-glossary.com■■■■■■■■
Experimenter bias refers to the iInfluence of the experimenter''s expectations or personal beliefs on . . . Read More
Randomization at psychology-glossary.com■■■■■■■■
Randomization refers to the process whereby individuals are assigned to study groups without biases or . . . Read More
Generalizability at psychology-glossary.com■■■■■■■
Generalizability refers to an extent to which research results apply to a range of individuals not included . . . Read More
Dependent variable at psychology-glossary.com■■■■■■■
A dependent variable is what you measure in the experiment and what is affected during the experiment. . . . Read More
Control group at psychology-glossary.com■■■■■■■
- Control group : control group refers to group of individuals in a study who are similar to the experimental . . . Read More
Construct validity at psychology-glossary.com■■■■■■
Construct validity: Construct validity refers to the test which is demonstrated to be a measure of a . . . Read More
Field experiment at psychology-glossary.com■■■■■■
Field experiment is defined as an experiment conducted in a real-world setting; an experiment that takes . . . Read More
Concurrent validity at psychology-glossary.com■■■■■■
Concurrent Validity refers to the extent to which test scores correlate with scores on other relevant . . . Read More
External validity at psychology-glossary.com■■■■■■
External validity refers to the degree to which findings can be generalized or extended to people, settings, . . . Read More