The following passage is quoted from: Teacher Investigations of Students’ Work: The Evolution of Teachers’ Social Processes and Interpretations of Students’ Thinking, a doctoral thesis by Michelle Heger Chamberlin. It provides information on the background and design principles for Case Studies for Kids.
Another source of information can be found in Beyond Constructivism: Models and Modeling Perspectives on Mathematics Problem Solving, Learning, and Teaching Chapter 13, “The Case for Cases” http://tcct.soe.purdue.edu/books_and_journals/models_and_modeling/powerpoints/ch13.swf
The Origin of Case Studies for Kids
Case Studies for Kids were originally
designed as a result of a multitiered teaching experiment (Lesh & Kelly,
2000; Lesh, et al., 2000). The overall goal of the research was for middle
school teachers to collaborate with researchers in developing performance
assessment activities, accompanying teaching materials, and respective design
principles so that other teachers could create similar activities. The activities
were to focus on deeper and higher order understandings of approximately ten
major mathematical ideas at each grade level. The research was conducted over
a 15week period in which teachers met with researchers weekly for twohour
seminars and worked together to express, examine, compare, test, refine, and
reach consensus about activities that were shown to be excellent for performance
assessment of their students.
The main criteria for judging the activities in development was to ask, “Do
the students’ solutions provide useful diagnostic information about
the students’ mathematical understandings?” In other words, when
the teachers observed their students working on the activities and when the
teachers examined their students’ final solutions, did the observations
and solutions reveal useful assessment information? To engage the teachers
in cycles of expressing, testing, and revising their performance assessment
activities and their associated models, the researchers involved the teachers
in various iterative activities:
As the teachers and the researchers worked to define rules for designing effective
performance assessment activities, they began to realize that the most promising
activities were ones that required students to reveal their thinking and to
continue thinking in an increasingly more productive manner while only needing
minimal intervention from the teacher. Specifically, the teachers and the
researchers began to realize that the activities had to be (a) selfadapting
in that the students would be able to interpret the activity meaningfully
from each of their different levels of mathematical ability without needing
the teacher to bring them all to a mathematical starting point first, (b)
selfdocumenting in that the students’ solutions would naturally reveal
how they were thinking about the problem, and (c) selfmonitoring in that
the students could assess their thinking on their own and could continue thinking
in productive ways without relying on the teacher or the researcher to prod
them on. The teachers and the researchers then began to realize that in order
for the activities to be selfdocumenting, the most successful mechanism was
to ask the students to create complex products such as descriptions, explanations,
or procedures for interpreting significant mathematical situations. By the
end of the study, the teachers and the researchers had refined their three
criteria into six guiding principles for designing Case Studies for Kids.
Six Design Principles for Case Studies for Kids
To develop Case Studies for Kids, designers rely upon six design principles that are based on the work of the teachers and the researchers described above and that have subsequently been refined by Lesh et al. (2000). Each principle is briefly described in this section and illustrated by referring to the case study, Departing On Time (See Appendix B). Departing On Time presents students with departure times for five different airlines. The client for the case study, the Ridgewood High School Spanish Club, needs help selecting an on time airline for an upcoming study abroad trip. Thus, students have to develop a procedure that the club can use to rank the five airlines from mostlikelytodepartontime to leastlikelytodepartontime. The activity is specifically designed to help students develop conceptual foundations for statistical concepts such as mean, standard deviation, spread, and frequency.
The first principle for designing a Case Study for Kids is called the Model
Construction Principle. This principle ensures that the solution to the case
study requires the construction of an explicit description, explanation, procedure,
or justified prediction for a given mathematically significant situation.
Such products externalize how the students interpret the situation and also
reveal the types of mathematical quantities, relationships, operations, and
patterns that they take into account. In the Departing On Time case study,
students are specifically asked to “Develop a procedure for ranking
the five airlines in terms of mostlikelytodepartontime to leastlikelytodepartontime.”
The second design principle is the Reality Principle. This principle could
also be referred to as the meaningfulness principle, and it relates to two
important characteristics of a case study. First, it requires the case study
to be designed so that students can interpret the activity meaningfully from
their different levels of mathematical ability and general knowledge. In the
Departing On Time case study, students relate to the idea that they want to
select an airline that is more likely to leave on time, and they quickly realize
that lower numbers in the table indicate more punctuality. Second, this principle
requires the case study to pose a problem that could happen in real life.
In the Departing On Time case study, selecting an airline that is most likely
to depart on time is a pragmatic problem.
The third design principle is the SelfAssessment Principle. This principle
ensures that the case study contains criteria the students themselves can
identify and use to test and revise their current ways of thinking. Specifically,
the case study should include information that the students can use for assessing
the usefulness of their alternative solutions, for judging when and how their
solutions need to be improved, and for knowing when they are finished. For
the Departing On Time case study, students can carry out strategies such as
finding the total or average number of minutes late for each airline or counting
the number of times that each airline departs on time. Then, they can return
to the data in the table to selfassess whether the results of their calculations
seem to reflect what they visually see in the data. As an example, students
often begin this problem by finding the average number of minutes late for
each airline. When they find that the averages are all nearly the same, they
return to the data and begin noticing that although the averages are the same,
the airlines differ in the amount of time that they are typically late when
they are late and in their frequency of being late. Such reflections typically
lead the students to revise their strategies for solving the case study and
to try different approaches such as counting the number of on time flights
for each airline or finding the average number of minutes late when the flights
are late.
The fourth principle, the Model Documentation Principle, ensures that while
completing the case study, the students are required to create some form of
documentation that will reveal explicitly how they are thinking about the
problem situation. Requiring external documentation of their thinking is beneficial
for both the teacher and the students. First, the documentation is helpful
for the teacher because it reveals how the students are interpreting and thinking
about the given situation. Second, the documentation is beneficial for the
students because when students externalize their thinking, it becomes easier
for them to selfassess or to reflect on their thinking. In other words, externalizing
their thinking helps students engage in metacognition. This principle is typically
accomplished in two ways. First, students are working in groups; thus, they
explicitly reveal their thinking when they communicate with each other to
carry out processes such as planning, monitoring, and assessing. Second, as
in the example case study, the problem is stated to require students to produce
explanations, procedures, or descriptions as part of their solution and to
explain their solutions in written letters. Together, these two requirements
produce documentations that reveal how students are thinking about the given
situation.
The fifth principle is the Construct ShareAbility and ReUsability Principle,
which requires students to produce shareable and reusable solutions. By
asking the students to produce products that can be used by others beyond
the immediate situation, case studies require students to go beyond personal
ways of thinking to developing more general ways of thinking, often resulting
in more powerful mathematics. In the Departing On Time case study, the students
are specifically asked to develop a ranking procedure that can be shared with
the Spanish club, which encourages the students to be more detailed in their
explanations of their solutions. In addition, the students are specifically
asked to make their procedure more general so that the Spanish club “may
use the procedure to rank additional airlines that they may identify at a
later time.”
The sixth principle, the Effective Prototype Principle, ensures that the case
study will be as simple as possible yet still mathematically significant.
The goal is for students to develop solutions that will provide useful prototypes
for interpreting other similar situations. In the Departing On Time case study,
the problem scenario is clear and simple – find the airlines that are
more likely to depart on time. Furthermore, students’ solutions usually
provide a useful prototype for interpreting other situations. For example,
some students solve the Departing On Time case study by counting the number
of on time departures for each airline. Such a process can serve as a prototype
for other situations in which frequency counts are appropriate.
Table 2 summarizes the six design principles by providing questions that can
be used to design a Case Study for Kids.
Table 2  Verification Questions for the Six Design Principles
Construction Principle 

Reality Principle 

SelfAssessment Principle 

Documentation Principle 

Shareability and ReUsability Principle 

Effective Prototype Principle 

Case Studies for Kids  History 