Integrating Students’ Prior Knowledge into Pedagogy

Colleen LewisGraduate School of Education

University of California, Berkeley

The Problem

“Part of the problem is that the subject is not widely taught at school,

so undergraduates arrive without having being streamed into those who

can do well and those who can't.”

Bornat, Dehnadi, & Simon, 2008

AP Test Taking Rates

1997 2009

300,000

200,000

100,000

Number of test takers

Source: College Board Exam Volume Data

2010 AP Test Takers (% Female)

Biology Statistics Calculus AB Computer Science

57.8%50.6% 48.6%

19.2%

Problem 2: Bimodal Distribution

Problem 3: Community Discourse

“The literature abounds in assertions of the existence of an aptitude for programming,

and of attempts to find a suitable predictor for that aptitude so as to avoid wasting time and effort

educating students who are unlikely ever to become good programmers.”

Simon et al. 2006

Problem 3: Community Discourse

• “innate talent for programming” • Lister et al., 2004

• “a fundamental ability” • Reges, 2006

• “Introductory classes should weed students out based on ability and potential”

• Barker, McDowell & Kalahar, 2009

What factors predict success?

• Problem solving• Explanation skills• Abstraction skills• Math experience• SAT scores• Programming pre-tests

Hypothesis

Student success is shaped by the degree to which they

make productive use of their non-programming competence

when learning to program.

Research Questions• What knowledge and skills do students use

when solving computer science problems?

• How can we build upon students’ non-programming knowledge?

• How can we integrate these techniques into curriculum?

Phase 1

Research Question:• What knowledge and skills do students use

when solving computer science problems?

Example Interview Problem: • If b is a Boolean variable, then the statement

below has what effect?

 b = (b == false);

Phase 2

Research Question:• How can we build upon students’ non-

programming knowledge?

Study Design• Design-based research • Recruit struggling students

Phase 3

Research Question:• How can we integrate these techniques into

curriculum?

Study Design• Techniques integrated into existing course• Quasi-experimental design

Example Analysis

What value is returned by WhatIsIt(4, 4)?

(define (WhatIsIt x n) (if (= n 1) x (* x (WhatIsIt x (- n 1))))

WhatIsIt Solution

(WhatIsIt 4 4)

(* 4 (WhatIsIt 4 3))

(* 4 (* 4 (WhatIsIt 4 2)))

(* 4 (* 4 (* 4 (WhatIsIt 4 1))))

(* 4 (* 4 (* 4 4)))

Using Critical Reading Skills(define (WhatIsIt x n) (if (= n 1) x (* x (WhatIsIt x (- n 1))))

01 WhatIsIt x n.02 If n equals 1, print x.

If n is not 1, then multiply x,03 oh okay so its recursive.

Critical Reading Skills

• Rephrasing• Summarizing• Re-reading

State

• What line of code is being executed?• What are the values of all variables? • What calls proceeded the current call?

• How can I change the line of code executed?• How can I change the values of variables?• How can I sequence procedure calls?

Tracking State04 So 4, 4.05 If x is -- n is 4,06 n is not equal 1 (points to if line), 07 so multiply x, which is 4,08 (writes 4)

Tracking State09 by WhatIsIt 4 3 10 (Writes 4 and 3)11 x is -- n is again not 1,12 so it will be 3 13 (Writes 3)

Experience with State

Tracking State

03 So it’s going to multiply 4 times WhatIsIt04 (writes 4 and “wii”)05 of x is not changing06 (writes 4),07 n is going to change to 308 (writes 3).

Tracking State09 Which will do 10 (writes 4)11 oh snap I was way wrong.12 Which is 4 times WhatIsIt of 4 and 213 (writes wii 4 2),

Tracking State

Problems

• Students have a rich set of non-programming skills before college.

• No explanations for why well prepared students fail to learn

• We do not know how to build upon this knowledge.

Approach

Phase 1• Identify techniquesPhase 2• Develop and refine teaching strategiesPhase 3• Analyze effectiveness

Thank you! Questions?

Colleen LewisGraduate School of Education

University of California, Berkeley