MDPI Research Basis
The research of the authors, as well as that conducted by notable research psychologists, neuropsychologists and math educators, confirm the approaches and interpretive definitions used in the MDPI. The Clinical Interview technique, used by the MDPI examiner in conducting the individual assessment, played a central role in the work of such seminal theorists as Piaget, Vygotsky, and Freud. Recently, Herbert Ginsburg has argued for the diagnostic utility of the clinical interview and its superiority over traditional standardized measures.
The need to incorporate the consideration of "process" in conducting a mathematics skills assessment was documented as far back as seventy-five years ago. Developmental theorist Heinz Werner cautioned that conclusions about a student's performance that were based entirely upon achievement scores could be quite misleading. He observed that individuals can arrive at a solution to a given task via a variety of distinctly different processes which are observable at the behavioral level. They are, he theorized, manifestations of underlying differences in the central nervous system. These differences, Werner argued, are, therefore, relevant in any assessment of an individual's learning ability and achievement.
Referencing assessments to neuropsychological frameworks, as suggested by Werner, is consistent with the work of Edith Kaplan, and others, who developed a methodology for neuropsychological assessment. More recently, Deborah Waber argued for the rethinking of learning disabilities in terms of a Child / World system. The concept was developed by her and her colleague, Jane Holmes-Bernstein. Dr. Holmes-Bernstein pioneered the neuropsychological approach to children. Waber & Holmes-Bernstein's data reinforces the notion that the key to meaningful assessment practices rests in the interaction between the child and the environment.
The Child -World System construct was extended to mathematics learning by Marolda and Davidson who defined mathematics learning styles (inherent intuitions and processing strategies brought to the circumstance of mathematics) and incorporated additional neuropsychological parameters into the assessment of students in mathematics. This work culminated in the development of the MDPI. The definition of mathematics learning styles was confirmed by the research of Patricia Davidson. In that work, statistical analyses documented the constellation of features that contributed to each learning style. Additional statistical analyses confirmed the reliability and validity of the MDPI in determining achievement levels in mathematics as well as assigning mathematics learning styles.
The qualitative aspects of performance incorporated by Marolda and Davidson were also examined by Ellen Boiselle. Boiselle confirmed associations between achievement and qualitative aspects of performance in mathematics. In addition, the associations between qualitative aspects of performance and neuropsychological measures were also corroborated.

In sum, the research of the authors, as well as the work of notable research psychologists, neuropsychologists and math educators, verify the approaches and interpretive definitions used in the MDPI.
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