Construct-Centered Design
One of the NCLT’s main goals is to develop a Center-wide approach for (a) mapping out the
knowledge domains (constructs) associated with nanoscale science and engineering (NSE) and
(b) developing instructional materials and assessments of that knowledge for various purposes,
including supporting instructional design and understanding how students’ ideas of nanoscale
science develop over time. To align learning research and the development of instructional
materials and assessment in a consistent, principled way, we developed a method consistent
with the contemporary literature on designing and constructing valid assessments 1,2 and
instructional materials3,4. Because the foundation of the process lies in the definition and
explicit specification of content that lies within NSE constructs, or big ideas, the process is
termed construct-centered design (CCD).
The process involves first unpacking a big idea of NSE, into the related sets of concepts that
define appropriate levels of “understanding” for a target population (e.g., 8th graders, high
school students in regular or AP science classes, engineering undergraduates etc.). Based upon
the unpacking, a set of claims is produced that specify the nature of student knowledge and
understanding, along with the evidence that would be required in student work to support a
specific knowledge claim or set of claims, and the tasks or performance situations that would
yield sufficient observable evidence.
What follows is a brief description of each step of the process. In laying out a sequential set of
steps, we note that the process is interactive and highly recursive, with information specified at
one stage clarifying and often modifying what was specified earlier.
Step 1. Select the big idea in which you are interested5.
Step 2. Identify the grade level of the students.
• Students at different grade ranges have different knowledge and experiences, which will
influence their learning.
Step 3. Unpack the big idea (construct).
Unpacking involves taking the big idea, breaking it apart and expanding the various concepts to
identify and describe the critical components important for understanding the big idea.
• Identify and clarify the scientific content contained within the big idea. What concepts
are critical for understanding the big idea? At what level and depth of understanding do
you expect learners to understand the concepts?
• Identify and describe what prior knowledge students will need to have.
• Identify and describe what alternative ideas or misconceptions students may have
regarding the content.
• Identify and describe any difficulties students may have in developing understanding of
the content
• Identify and describe illustrative phenomena that demonstrate important
understandings and scientific concepts within the big idea. The phenomena selected
should explicitly link to key ideas and help make the scientific ideas plausible for
students. The phenomena should make the key concepts visible and purposely support
development of student understanding of the key concepts.
Step 4. Create a claim.
A claim describes the types of understanding expected of students regarding a particular
construct, concept, or idea.
• In constructing a claim, avoid vague terms like to know and to understand. Rather,
claims should be descriptive and specific, using verbs describing what students will be
able to do cognitively. This clarifies the nature of what they know or understand and how
they know it.
Step 5. Specify what evidence you will accept that a student has the desired
knowledge.
Evidence describes in detail the specific student behaviors, or performances, and/or work
products that you would defend as indicative that the claim has been satisfied.
• Specify the features of student products and performances that you expect to see and
that form the basis for any judgment in support of the claim.
Step 6a (assessment). Design particular tasks, questions or situations (assessment
tasks) that will allow a student to respond in such a manner to generate data that will allow you
to make a judgment about whether sufficient evidence exists to support the learning claim.
• A single task or situation may provide evidence for more than one claim.
• Multiple tasks may be necessary to assess a single claim.
Step 6b (instructional materials). Design particular learning activities (learning
tasks) that will support the development of student knowledge and skills such that they will be
able to produce or execute the products, behaviors or performances that were deemed sufficient
evidence to support the learning claim.
Step 7a. Review assessment task(s).
Factors to consider include:
• Is the assessment task and context likely to be comprehensible to students?
• Is the assessment task appropriately linked to knowledge required for understanding
the desired knowledge?
• Is the assessment task level-appropriate for students (e.g., content, language, etc.)?
Step 7b. Review learning task(s).
Factors to consider include:
• Is the activity likely to be comprehensible to students?
• Does the activity support the development of understanding of a key aspect of the
big idea?
• Do target students have the necessary prerequisite knowledge to do the activity?
• Are students provided with the opportunity to practice using knowledge in a
meaningful situation?
• Are students provided with the opportunity to think about (and make sense of) what
they've learned?
References:
1- Pellegrino, J.W., Chudowsky, N., & Glaser, R. (Eds.). (2001). Knowing what students know:
The science and design of educational assessment. Washington, DC: National
Academies Press.
2- Mislevy R. J., Steinberg, L. S., Almond R. G., Haertel, G. D., & Penuel, W. R. (2003).
Leverage points for improving educational assessment (PADI Technical Report. No. 2).
Menlo Park, CA: SRI International [viewed electronically].
3- Wiggins, G. P., & McTighe, J. (1998). Understanding by design. Alexandria, VA: Association
for Supervision and Curriculum Development.
4- Krajcik, J.S., McNeill, K. L., & Reiser, B.J. (2007). Learning-goals-driven design model:
Developing curriculum materials that align with national standards and incorporate
project-based pedagogy. Science Education, 92(1), 1-32.
5- Stevens, S. Y., Sutherland, L., Schank, P., & Krajcik, J. (draft, 2007). The big ideas of
nanoscience. Retrieved June 2, 2007 from http://hice.org/PDFs/Big_Ideas_of_Nanoscience-20feb07.pdf