The Motivation Assessment Scale: reliability and construct validity across three topographies of behavior.
The MAS has weak psychometrics—use it only as a quick screen, not your main FBA.
01Research in Context
What this study did
The team tested the Motivation Assessment Scale (MAS) on the adults with intellectual disability.
They checked if the four subscales (sensory, escape, attention, tangible) really matched the data.
Each person had three problem behaviors rated by staff using the 16-item checklist.
What they found
The MAS showed poor reliability. Different raters often disagreed on the same behavior.
The factor structure did not line up with the four intended subscales.
In plain words, the MAS scores were shaky and did not measure what they claimed to measure.
How this fits with other research
Fox et al. (2001) later showed the Questions About Behavioral Function (QABF) beat the MAS.
Their study found QABF scores lined up better with real functional analysis results.
Matson et al. (1999) added that treatments based on QABF worked better than standard care.
Rajaraman et al. (2022) shifted the debate: even if a tool’s reliability is weak, the treatments it guides can still succeed.
Why it matters
Stop using the MAS as your only FBA tool. Pair it with direct observation or switch to QABF. Your treatment plan will rest on firmer ground.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Add the free QABF checklist to your intake packet and compare its results to your MAS data.
02At a glance
03Original abstract
The psychometric properties of the Motivation Assessment Scale (MAS) were examined. Specifically, reliability, internal consistency, and construct validity were estimated using 90 ratings of different problem behaviors among 86 individuals with mental retardation. Data were analyzed under conditions of (a) three topographies of problem behavior and (b) two methods of calculation. Although reliability and internal consistency were generally poor, the results depended upon the above conditions. Factor analysis revealed that the four factors of the MAS differed from the subscale structure obtained in this study, proposed by the authors of the MAS. Thus, the construct validity of this scale was ambiguous. It is concluded that the MAS should be employed in conjunction with other instruments to assess the functional characteristics of problem behavior with individuals who have mental retardation.
Research in developmental disabilities, 1998 · doi:10.1016/s0891-4222(97)00047-4