Verbal Behavior SCoRE

The verbal behavior Stimulus Control Ratio Equation (SCoRE; Mason & Andrews, 2019) quantifies the speaking repertoire of individuals with autism and other language disorders by sampling the strength of four functional language domains and comparing them against a model of fluent speaking. Data for the SCoRE are gathered using a functional analysis of verbal behavior (Lerman et al., 2005), that answers the question: What controls the speaker's responding?

Research on verbal behavior has identified four primary sources of control over language:

• Tact (i.e., labeling), controlled by the physical environment (Horne & Lowe, 1996)

• Mand (i.e., requesting), controlled by restricted access (Michael, 1982a)

• Intraverbal:

  • Echoic (i.e., echoing), controlled by an imitative verbal stimulus (Michael, 1982b)

  • Sequelic (i.e., conversing), controlled by other people's verbal behavior (Vargas, 1982)

In contrast to fluent speakers, who show proportionality across these four sources of control (Sundberg, 2007), speakers with stimulus overselectivity show different levels of response strength (Cochran, 1950; Lovaas et al., 1979). SCoRE identifies the extent to which the speaking repertoire is balanced.

The speaker's SCoRE is then calculated using the following formula:

SCoRE quantifies the speaker's present level of functional language performance, prescribes a most-to-least prompt hierarchy for errorless language learning, and can be used to show progress over time.