Refers to when initial response rates in baseline are weaker due to a subject needing to get warmed up.

Any uncontrolled participant-related variables that may interfere with the outcomes of an intervention and therefore the internal validity of an experiment.

Any uncontrolled variables in the treatment setting that could impact the outcomes and/or the effectiveness of an intervention and therefore the internal validity of the experiment.

Refers to the changes in an individual’s behavior due to the presence of an observer.

Refers to an improvement in responding from the opportunity to practice a behavior, specifically during prolonged baseline measurement periods.

Refers to the changes in a subject over the course of the study that result from natural growth and development.

Uncontrolled variables related to the environment, the measurement tools, or a data collector’s behavior that may interfere with the measurement of behavior and therefore impact the outcomes and/or the effectiveness…

Uncontrolled environmental variables that may interfere with the outcomes and/or the effectiveness of an intervention and therefore the internal validity of the experiment.

Result can elicit a reflexive behavior.

Reinforcement that is accessed without meeting the response requirements of the contingency.

A reduction in the number of study participants, which can impact the validity and reliability of the findings and compromise the integrity of the data.

Refers to the changes in operant responding due to the repeated presentation of a particular antecedent stimulus.

An experimental replication of a previous study in which the researcher intentionally changes one or more features of a prior experiment.

The extent to which an experiment strongly shows that changes in the dependent variable are a direct result of the independent variable and not the result of some other uncontrolled…

An experimental replication of a previous study in which the researcher exactly duplicates a previous study using the same subjects as the original study.

An experimental replication of a previous study in which the researcher exactly duplicates a previous study but uses different subjects from the original study.

The extent to which the results of a study can be generalized to other settings, behaviors, or subjects.

PTB founder Dana Meller helps connect each of the validities to the validity of this explanation.

It's particularly meaningful to be able to tell validity, social validity, internal and external validity apart. PTB co-founder Dana Meller has some tips to do just that.

PTB co-founder Dana Meller breaks down a BCBA® mock exam question that explores the difference between measurement confounds and subject confounds, how they relate to threats to internal validity in ABA research. Refer to BCBA® Task List (5th ed.) Section D-2: Distinguish between internal and external validity.

PTB co-founder explains the different types of validity in ABA. Refer to BCBA® Task List (5th ed.) Section D-2: Distinguish between internal and external validity.