Tuesday, September 29, 2015

Measurement of Behaviors

When asked what had been his main contribution, Skinner, the father of applied behavior analysis, used to say the measurement of behaviors.

ABA is a scientific approach to understanding and changing behaviors. Science relies on direct and objective observation, measurement and experimentation of phenomena, which leads to effective interventions.
We start by taking baseline data: the behaviors are measured in the absence of the treatment variable. This gives us a measurement of the behavior before intervention is applied and allows for comparison further on for evaluation of treatment purposes. In other words baseline data is used to measure effectiveness of the intervention plan.

In order to measure behaviors operational definitions are a “must.” We need an accurate, observable and objective description of behaviors, including data on events that precede and follow the occurrences of the behaviors, and the frequency, duration and intensity of the problem behavior. It is a count of the present (i.e., pre-treatment) level of performance.

        Allows all team members to identify and discuss the same behavior

        Ensures consistency when implementing behavior plans

Direct and frequent measurement enables a dynamic, data-based decision making process concerning the continuation, modification or termination of treatment. Without this information, an ineffective treatment could be continued or an effective treatment could be discontinued based on subjective judgment. Continuous evaluation of success and failures in the treatment allows us to make the necessary changes in the behavior modification plan. Through measurement we “hear” our clients’ messages.
Additionally, measurement enables practitioners to be accountable to clients, employers and referral agencies.  

Because behaviors occur within and across time, they have three dimensional quantities:

       Frequency: Instances of a behavior. Behaviors can be counted. (i.e. Johnny engages in 7 tantrums per day)
       Duration: Behaviors occur during time. Therefore, the duration of behaviors can be measured (i.e. each tantrum episode lasts 5 to 7 minutes)
       Magnitude: The intensity of the behavior. One standard way is to define the intensity as followed:
       Severe: the behavior may be harmful or dangerous to self and/or others.

       Moderate: the behavior is disruptive to the life of the individual and/or others.

       Mild: the behavior is bothersome to others.

Usually a simple tally of number of occurrences is enough. For example, the number of times a student raises his hand. The behavior must have a clear onset and offset (beginning and end). The observation period must be reported (i.e. 10 times per hour, day, week, etc.)
When the behavior does not present a clear beginning and end, percentage of responses per unit of time is used (i.e. students engages in eye contact 20% of the time per session) 

Comparing measures without referencing to units of time can lead to faulty interpretations. For example, stating that Will reads 100 correct words is not enough. Time must be reported. For example, 100 correct words per hour, session, etc.

Oftentimes data isn’t taken correctly because practitioners don’t know how to take the data or track the wrong behavior. This is one of the reasons why interventions have to be supervised by knowledgeable professionals. Board Certified Behavior Analyst are the gold standard in the field.   
Once I heard the phrase “What gets measured can be improved.” And this applies to our practice.

As a parent or teacher, be sure the professionals working with your child are experienced and knowledgeable enough to ensure the effectiveness of their treatments. And monitor regularly, at least monthly, the data. The answer is usually there.

Daniel Adatto, BCBA


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