Internal and External Validity in Research

Extraneous Variable

An uncontrolled variable influencing the dependent variable.

Internal Validity

A validity between two or more variables should be unambiguous as to what it means rather than being due to "something else".

Confounding Variable

Outside factor affecting both independent and dependent variables.

Intervening Variable

Explains relationship between independent and dependent variables.

Moderating Variable

Influences strength/direction of independent-dependent relationship.

Demographic Variable

Characteristics used to categorize participants in research.

Instrumentation

Method of measurement that can affect study outcomes.

Instrumentation Decay

Changes in measurement tools affecting validity over time.

Data Collector Characteristics

Attributes of individuals collecting data that may bias results.

Data Collector Bias

Unconscious distortion of data by the collector.

Subject Characteristics

Referred as selection bias, or a subject characteristics threat.

Loss of Subjects

Dropout of participants affecting study outcomes; AKA 'Mortality Threat'

History

Unplanned events during study affecting participant responses.

Location

When collecting data, intervention is carried out in particular where it may create alternative explanations for results

Maturation

Changes in participants over time affecting outcomes.

Testing

Use of instruments that may influence participant responses.

Planned Ignorance

Deliberate avoidance of certain information by researchers.

Standardization

Uniform procedures to minimize bias in data collection.

Coping Strategies

Methods individuals use to manage stress affecting outcomes.

Classical Music Effect

Impact of music on anxiety levels in patients.

Education and Income

Link between education level and job skills development.

Pretest

Initial test that may influence subsequent performance.

Questionnaire Studies

Research method using surveys for data collection.

External Validity

Generalizability of study findings across contexts.

Hawthorne Effect

In understanding the participant's attitude, this effect is the behavior change due to awareness of being studied.

John Henry Effect

In understanding the participant's attitude, this effect is the control group that compensates for perceived disadvantage.

Regression Threat

Change in extreme groups affecting study results.

Implementation Threat

Variability in treatment administration affecting outcomes.

Random Selection

Choosing participants randomly to enhance validity.

Sampling Model

Framework for selecting participants in research.

Proximal Similarity Model

Generalizing results to similar persons or settings.

Representative Sample

Sample accurately reflects the target population.

Extraneous Events

Uncontrolled factors that may influence study results.

Mortality Threat

Loss of participants affecting study outcomes.

Maturation Threat

Changes in participants over time influencing results.

Statistical Power

Ability to detect an effect if one exists.

Reliability

Consistency of a measure across time.

Validity

Accuracy of a measure in assessing what it intends.

Control Group

Group not receiving treatment for comparison.

Comparison Group

Group receiving alternative treatment for analysis.

Data Collection

Process of gathering information for analysis.

Study Replication

Conducting studies to verify original findings.

Generalization

Applying findings to broader contexts or populations.

Historical Perspective

Understanding past concepts to inform current research.

Age, Gender, Education Level

These are the Common Demographic Variables

Threats to Internal Validity

Subject Characteristics, Loss of Subjects (Mortality), Location, Instrumentation, Data Collector Bias, Testing, History, Maturation, Attitude of Research Participants

Attitude of Research Participants

How research participants view a study and participate in it can also threaten internal validity.

Threats to External Validity

Threats that are evaluated by tests of the extents, to which one can generalize across various kinds of people,

Careful Planning

To EMPHASIZE, because of this, various threats to internal validity can be reduced

Collecting Additional Information

To EMPHASIZE, with planning this also requires (answer) before a study begins or while it takes place.

Minimizing Threats to International Validity

Standardize the conditions under which the study occurs, Obtain more information on the subjects of the study, Obtain more information on the details of the study, and choose an appropriate design

Attitude of Subjects

May appear that the experimental group is performing better as a result of the treatment