Research Issues in Developing Strategic Flexibility: What and How

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# Research Issues in Developing Strategic Flexibility: What and How - PowerPoint PPT Presentation

Presenters: Christine Carrino Gorowara  University of Delaware Dawn Berk  University of Delaware Christina Poetzl  University of Delaware Jon R. Star  Michigan State University Susan B. Taber  Rowan University Discussant: John K. Lannin  University of Missouri-Columbia.

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Presenters:

Christine Carrino GorowaraUniversity of Delaware

Dawn BerkUniversity of Delaware

Christina PoetzlUniversity of Delaware

Jon R. StarMichigan State University

Susan B. TaberRowan University

Discussant:

John K. LanninUniversity of Missouri-Columbia

NCTM Presession 2005

Symposium Overview
• Introduction
• Description of Projects
• MSU Project
• UD Project
• Challenges of Researching Strategic Flexibility
• Audience Feedback

NCTM Presession 2005

Problem #1: Find x if 4(x + 5) = 80.

Problem #2: Joan drove 200 miles in 3.5 hours.

How far can she drive in 14 hours?

For each problem—

• Solve, using any strategy you like.
• Solve again, using a different strategy.
• Determine which strategy is better, and why.
• Try to change the problem so that the other strategy is now better.

NCTM Presession 2005

4(x + 5) = 80

x + 5 = 20

x = 15

4(x + 5) = 79

x + 5 = 79/4

x = 59/4

Problem #1: Find x if 4(x + 5) = 80

[Find x if 4(x + 5) = 79]

Strategy 1:

Strategy 1 with changed problem:

4(x + 5) = 80

4x + 20 = 80

4x = 60

x = 15

4(x + 5) = 79

4x + 20 = 79

4x = 59

x = 59/4

Strategy 2:

Strategy 2 with changed problem:

NCTM Presession 2005

What counts as different?
• Different number of steps
• 3 lines? 4 lines?
• Different sequence of steps
• Distribute first? Divide first?
• Other characteristics?

NCTM Presession 2005

Problem #2: Joan drove 200 miles in 3.5 hours. How far can she drive in 14 hours?

[Joan drove 200 miles in5hours…]

Strategy 1:

Strategy 1, with changed problem:

? x 3.5 hours = 14 hours

4 x 3.5 hours = 14 hours

4 x 200 miles = 800 miles

? x 5 = 14 hours

14/5 x 5 = 14 hours

14/5 x 200 miles = 560 miles

Strategy2, with changed problem:

Strategy 2:

Joan drives 200/5 mph, or 40 mph.

In 14 hours, she drives 14 x 40 miles, or 560 miles.

Joan drives 200/3.5 mph.

In 14 hours, she drives 14 x 200/3.5 = 800 miles.

NCTM Presession 2005

What counts as different?
• Different number of steps
• Different multiplicative relationships used
• Scale factor between two sets of hours vs. scale factor between hours and miles
• Other characteristics?

NCTM Presession 2005

Introduction
• Many problems can be solved with a variety of strategies
• Important goal for students is to develop flexibility in the use of strategies, which means that they:
• Know multiple strategies for solving a class of problems
• Select from among those strategies the most appropriate for solving a particular problem

NCTM Presession 2005

Defining Flexibility
• Proficiency in executing a range of strategies

AND

• Ability and disposition to choose wisely among those strategies with respect to a particular goal

NCTM Presession 2005

Related Work
• Our notion of “flexibility” is related to but distinct from other terms
• Adaptive expertise (Baroody & Dowker)
• Procedural fluency, strategic competence (NRC, 2001)
• Conceptual knowledge, procedural knowledge (Hiebert, 1986)
• Informed by research on:
• Strategy development in developmental psychology(e.g., Siegler)
• Problem solving (e.g., Schoenfeld, Silver)
• Strategy choice in arithmetic(e.g., Baroody, Fuson, Carpenter)

NCTM Presession 2005

Importance of Flexibility
• When flexible, students are more successful on transfer problems (e.g., Resnick, 1980; Schwartz & Martin, 2004; Carpenter et al, 1998)
• When not flexible, teachers are less likely to promote flexibility in their students (Hines and McMahon, 2005)

NCTM Presession 2005

Terms in this Talk
• Variations in terms across two projects
• MSU:
• Flexibility
• Appropriate or Best
• UD:
• Strategic Flexibility
• Wise/Unwise

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Challenges (Preview)

#1:What strategies are different?

#2:What strategies are “best”?

#3:How can we tell when a student is flexible?

#4:How do we develop strategic flexibility?

NCTM Presession 2005

MSU Project Description

NCTM Presession 2005

MSU Project Team
• PI: Jon Star
• Howard Glasser
• Mustafa Demir
• Kosze Lee
• Beste Gucler
• Kuo-Liang Chang
• Collaborator:
• Bethany Rittle-Johnson, Vanderbilt University

NCTM Presession 2005

• Work with students with minimal knowledge of strategies in problem class
• Provide brief instruction with no worked-out examples and no strategic instruction
• Provide minimal feedback
• Observe what strategies develop
• Conduct problem solving interviews to explore rationales behind strategy choices
• Implement and evaluate instructional interventions

NCTM Presession 2005

Instructional Interventions
• Students asked to re-solve previously completed problems using a different ordering of steps (Star, 2001; 2002)
• Explicit strategy instruction
• Strategy instruction is provided after students have achieved basic fluency and differentiated domain knowledge (Schwartz & Bransford,1998)

NCTM Presession 2005

Method
• 134 6th graders (83 girls, 51 boys)
• 5 1-hour classes in one week (Mon - Fri)
• Class size 8 to 15 students; worked individually
• Pre-test (Mon), post-test (Fri)
• Domain was linear equation solving

3(x + 1) = 12

2(x + 3) + 4(x + 3) = 24

9(x + 2) + 3(x + 2) + 3 = 18x + 9

NCTM Presession 2005

Instruction
• 30 minute benchmark lesson
• Combine like terms, add to both sides, multiply to both sides, distribute
• How to use each step individually
• Not shown how to chain together steps
• No strategic or goal-oriented instruction
• Not told when to use a step
• No worked examples of solved equations

NCTM Presession 2005

Alternative Ordering Treatment
• Random assignment by class
• AO treatment vs. AO control
• Solve this problem again, but using a different ordering of steps
• AO control group solved new but isomorphic problem

3(x + 1) = 12

4(x + 2) = 24

NCTM Presession 2005

Explicit Strategy Instruction
• Random assignment by class
• Strategy instruction vs. no strategy instruction
• At start of 2nd problem solving class, 3 worked examples presented to strategy instruction classes
• “This is the way I solve this equation.”
• Problems solved with atypical, ‘better’ strategy
• No notes taken by students
• Total time was 8 minutes of supplemental instruction

NCTM Presession 2005

Assessing Flexibility
• When I work on equations, I always use the same steps, in the same order (true/false)
• Figure out ALL possible NEXT steps that can be done on

2(x + 3) + 6 + 4x + 8 = 4(x + 2) + 6x + 2x

• Use the “combine like terms” step on

2(x + 1) + 5(x + 1) = 14

• Given this partially solved equation, what step did the student use to go from the first line to the second line?

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Results
• AO Treatment students significantly more flexible
• 54% treatment
• 41% control
• Strategy instruction led to significantly more flexibility
• 53% strategy instruction
• 45% no strategy instruction
• No significant interaction effect

NCTM Presession 2005

UD Project Description

NCTM Presession 2005

UD Project Associates
• Research Collaborators:
• Jim Hiebert
• Yuichi Handa
• Instructional Collaborators:
• Eric Sisofo
• James Beyers
• Laurie Goggins

NCTM Presession 2005

Context of the Study
• Domain: Missing-value proportion problems
• Participants: Pre-service K-8 teachers (n = 148)
• Familiar with missing-value proportion problems
• Many identified cross-multiplication as THE strategy for solving missing-value proportion problems
• Setting: Mathematics content course
• Semester-long focus on rational number concepts
• 4 proportional reasoning lessons taught at end of semester

NCTM Presession 2005

Example of Students’ Thinking

It takes 9 minutes to read 10 pages. How many minutes will it take to read 500 pages?

The criteria the group used to decide "best" strategy was instructive. They seemed to choose strategies that had a more formal appearance or ones that were similar to what someone remembered having learned before.

In solving one problem, a student suggested early in the conversation that:

• because 10 pages would take 9 minutes to read, and
• because 500 pages is 50 times that number of pages,
• 500 pages should take 50 times longer to read, and
• 50 x 9 = 450, so it would take 450 minutes to read 500 pages.

NCTM Presession 2005

Example of Students’ Thinking (cont’d)

After the student explained this several times so the others understood, the group wondered whether this was right. They had convinced themselves that the answer was right but wondered whether this is what they should be doing. "I'm not sure this is right because I don't think it's even a method." "Yeah, it seems too easy." "I think we should do it another way.”

The group ended up writing a proportion and using cross-multiplication, congratulating the student who thought of this because they all agreed this looked much better. They were surprised to find they got the same answer both ways (even though they seemed convinced that the first strategy had given them the right answer).

NCTM Presession 2005

Instructional Goals
• Develop a recognition of, appreciation for, and ability to use multiple strategies
• Cross-multiplication
• Unit rate
• Scale factor
• Scaling up/down
• Develop an ability to analyze a given problem and choose “wisely” from among a range of strategies
• Both computational and conceptual benefits

NCTM Presession 2005

x 50

x 50

Examples

It takes 9 minutes to read 10 pages. How many minutes will it take to read 500 pages?

Scale Factor Strategy:

10 pages: 9 minutes

500 pages: x minutes

500 pages: 450 minutes

Unit Rate Strategy:

9/10 minutes per (1) page

500 pages x 9/10 minutes per page

= 450 minutes

NCTM Presession 2005

Instructional Design
• Multiple strategies were identified and named.
• Students were asked to compare and contrast strategies for solving a given problem.
• Students were encouraged to choose strategies that capitalized on particular number relationships in the problem.

NCTM Presession 2005

Data Collection
• Pre/Post Tests (n = 148), Delayed Post Test (n = 53)
• 6 items: Solve using 1 strategy
• 2 items: Solve using 2 strategies
• Pre/Post Interviews (n = 22)
• 4 items: Solve using 1 strategy
• 1 item: Solve, given first step of strategy
• 1 item: Choose “best” among 3 worked solutions

NCTM Presession 2005

Coding Scheme
• Correctness
• Three measures of flexibility
• Number of strategies used across problems
• “Wise” choice of strategy on a given problem
• Ability to solve same problem using multiple strategies

NCTM Presession 2005

Results

Significant increase in:

• Number of problems solved correctly
• Number of strategies used across all problems
• Number of problems on which a “wise” strategy was used
• Use of multiple strategies on a given problem

NCTM Presession 2005

Comparing our Projects

NCTM Presession 2005

Challenges

#1:What strategies are different?

#2:What strategies are “best”?

#3:How can we tell when a student is flexible?

#4:How do we develop strategic flexibility?

NCTM Presession 2005

Challenge #1:What strategies are different?
• Different ways of representing the solution (e.g., graphically vs. symbolically)
• Number of lines/steps
• Different sequence of steps
• Steps ‘chunked’ vs. not ‘chunked’
• Different structural elements (e.g., number relationships) used

NCTM Presession 2005

Addressing Challenge #1:What strategies are different?
• MSU:
• Different sequence of steps
• UD:
• Different number relationships used

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4 

4 

200/3.5

200/3.5

Scale Factor

Unit Rate

Cross-Multiplication

NCTM Presession 2005

Reasons for our Choices
• MSU: Different sequence of steps
• Relatively simple way to begin looking at multiple strategies
• Bottom-up classification of “different”
• UD: Different number relationships
• Different computations result
• Different concepts about proportions are illuminated (e.g.,that the scale factors are equal, that the unit rates are equal, that the cross-products are equal)
• Top-down classification of “different”

NCTM Presession 2005

Challenge #2:What strategies are “best”?
• For what purpose(s)?
• Speed
• Accuracy
• Generalizability
• Preference
• Elegance
• Conceptual illumination
• For whose purpose(s)?
• Learner
• Instructor/Researcher
• Discipline

NCTM Presession 2005

Addressing Challenge #2:What strategies are “best”?
• MSU:
• Strategies with fewer steps
• Strategies with low cognitive load
• Bottom-up classification of “best”
• UD:
• Strategies taking advantage of simple (whole-number) multiplicative relationships between related values
• Top-down classification of “best”

NCTM Presession 2005

Reasons for our Choices
• MSU:
• Least mental effort
• Efficiency/Elegance (Disciplinary values)
• UD:
• Least mental effort
• Accuracy
• Conceptual illumination

NCTM Presession 2005

Challenge #3:How can we tell when a student is flexible?
• Competence vs. Performance: False Negative?
• Lack of variety in strategies does not necessarily indicate an inability to use multiple strategies
• Compliance vs. Disposition: False Positive?
• Greater variety of strategies following instruction does not necessarily indicate a disposition to be flexible

NCTM Presession 2005

• MSU:
• Competence vs. Performance: Creative assessments
• Compliance vs. Disposition: Not so much of an issue
• UD:
• Compliance vs. Disposition: Assessments over time
• Competence vs. Performance: Not so much of an issue

NCTM Presession 2005

Challenge #4:How do we develop strategic flexibility?
• Awareness of other strategies and competence in executing other strategies are necessary, but not sufficient
• Prior knowledge may play a role

NCTM Presession 2005

Draw attention to strategy choice…

• Manipulate problem features
• Problems must be complex enough to have multiple different solutions, yet simple enough so that the students can solve them
• Structure of problem and number choice should highlight appropriateness of various strategies

NCTM Presession 2005

Addressing Challenge #4 (continued):How do we develop strategic flexibility?

Draw attention to strategy choice…

• Name strategies or strategy elements
• Legitimizing effect
• "I'm not sure this is right because I don't think it's even a method."
• Reifying effect
• For example: performance of students in AO treatment

NCTM Presession 2005

Closing Thoughts
• Studying strategic flexibility involves making a set ofjudgments about what counts as different and what counts as best.
• Measuring strategic flexibility involves measuring students’ perceptions, motivations, and intentions in addition to strategy choice, and/or measuring strategy choice over time.
• Developing strategic flexibility involves shifting students’ focus from the solution product to the solution process.

NCTM Presession 2005

Thank You!
• Christine Carrino Gorowara cargoro@udel.edu
• Dawn Berk berk@udel.edu
• Christina Poetzl cpoetzl@udel.edu
• Jon R. Star jonstar@msu.edu
• Susan B. Taber taber@rowan.edu

NCTM Presession 2005

What counts as different?[Examples with Original Problem]

Different relationships between the given values being used:

• Strategy 1 uses the relationship between number of hours already driven and number of hours to be driven.

4 (# hours already driven) = # hours to be driven, so

4 (# miles already driven) = # miles to be driven

• Strategy 2 uses the relationship between number of hours already driven and number of miles already driven.

200/3.5 (# hours to be driven) = # miles to be driven

NCTM Presession 2005

What counts as different?[Examples with Changed Problem]

Different relationships between the given values being used:

• Strategy 1 uses the relationship between number of hours already driven and number of hours to be driven.

14/5 (# hours already driven) = # hours to be driven, so

14/4 (# miles already driven) = # miles to be driven

• Strategy 2 uses the relationship between number of hours already driven and number of miles already driven.