Overview
The LAS is rooted in cognitive developmental theory. As a graduate student, it's designer, Theo Dawson, focused on Piagetian and neo-Piagetian developmental theory. She was particularly influenced by Piaget, Kohlberg, Armon, Commons, and Fischer. The underlying principles of lectical assessment enjoy an excellent fit with Fischer's skill levels, so Dawson adopted the skill level definitions for lectical levels.
Much of the validity and reliability testing of the LAS has been done with the help of Rasch analysis, a psychometric technique that tests the extent to which an assessment taps a latent dimension.
This web site is an introduction to Lectical assessment. You will need a strong grounding in the developmental literature to fuly grasp what you read here. Our reference lists are a good place to start.
Caveats & cautions
Before you begin working with this scoring manual, we feel obligated to caution you that learning to produce accurate and reliable Lectical™ ratings is a difficult and time-consuming process. It should be understood that these pages offer more of an introduction to the LAS than training in Lectical™ analysis. Moreover, it is illegal for you to (1) call yourself a Lectical™ analyst unless you are certified by the Developmental Testing Service, Inc., or (2) claim that your data were scored by a Lectical™ analyst unless they were scored by a Lectical™ analyst certified by the Developmental Testing Service, INC.
Introductory material
If you have not already done so, read the introductory material in the public section of the site. It is important that you become familiar with the concept of hierarchical complexity, the notion of layers of structure, and other important concepts.
Domain content
Your can enhance your understanding of the structural features of skill levels by studying the domain pages in the menu on the left. These pages provide research-based descriptions of reasoning at different skill levels for a range of content domains. All of these descriptions are based Descriptions of domain content are presented for two reasons. First, examples of the content associated with Lectical™ levels can help trainees to understand abstract notions like logical structure and hierarchical order of abstraction. Second, knowledge about the conceptual content associated with Lectical™ levels is useful to a wide range of educators and researchers interested in cognitive development. Reference material can be found on the DTS site. We ask that authors cite the original research papers rather than this web site whenever possible.