what is the difference between validity and reliability

The best way to measure accuracy is recording a situation such as an ABA session and compare the data that was taken against the true value.įor example, if you are recording the number of spontaneous tacts in an ABA session and you record 72 during the session, but when you watch a video of the session and you record data without any distractions it comes up as 92, then the data is not accurate. The biggest threat to accuracy is human error. In an effort to help you study for your BCBA exam more effectively, this post is written in a “study note” form rather than as a long form blog post. Happy Studying!Īccuracy measures whether or not the value of a behavior being recorded represents the true value of the behavior. Simply put, it measures if the ABA therapist scored the behavior correctly. Understanding (Applied Behavior Analysis) ABA terms is critical for both being an effective ABA therapist and passing your BCBA exam. This article is useful for registered behavior technicians (RBT) or students who are studying to become board certified behavior analysts (BCBAs). $^1$ Cronbach's alpha is one of measures of internal consistency from reliability standpoint.In this brief blog article, we will examine the difference between accuracy, reliability and validity. If 'systematic error' were easy to distinguish from 'random error' without assumptions, there would be no frictions between reliability and validity. Thus, what the reliability approach will tend to pre-include into the error term, the validity approach will ascribe to the complexity, the multi-aspect, multi-symptom nature of the trait (and decide whether it is still the same construct or is already a battery of different ones). Validity stance regards the overall score by the scale as if it were the external criterion validity is interested in that item-to-total correlation, rather than in how well items duplicate each other. The lesser is the error the more item-item homogeneous is the scale. Reliability stance believes that the measured trait is simple, unifactor structure each item measures it and just it + is liable to some random error.

They seem to be two different (and perhaps competitive) paradigms about correlations observed among the items constituting the scale.

As seen for example with the term 'internal consistency'$^1$. Often seen as two different facets of an instrument functioning, reliability and validity sometimes are difficult to separate conceptually from each other.

Reliability of a psychometric scale is its correlation with its own 'true' score, and uncorrelation with extraneous random factors.

Validity of a psychometric scale is its correlation with the trait supposed being measured (called criterion), and uncorrelation with extraneous systematic factors.

What is the difference between validity and reliability