Problem Solving is as Easy as ABCD

Sarah E. Jackson
Assistant Professor of Economics
The Petroleum Institute, Abu Dhabi
Jot down 2-4 questions you might ask
on a homework assignment or an exam
◦ What would an ideal answer look like?
◦ How likely is it your students will give you an
ideal answer?
◦ Could a student get a good grade without really
understanding the concept?
◦ Could a student arrive at a different answer but
still be correct? If so, how would you grade it?
◦ Would you like to be able to expect more?
What answers would you expect for:
◦ You were at the mall & saw a cool TV. You were
willing to pay $650 but it was priced at $725 so
you didn’t buy it. The next week you find out you
won the TV! Your friend offers to buy it from you
for $700. Should you sell it? Why or why not?
◦ Mary can paint 6 walls or tile around 2 sinks in
one day. Marcus can paint 10 walls or tile around
5 sinks. Who should specialize in tiling? Why?
◦ Are poor people better off in a free market
economy or a centrally planned economy? Why?
How to Solve It, George Polya, 1945
◦ Four steps to solve math problems
Understand the problem
Devise a plan
Carry out the plan
Immediate benefits
◦ Helps student work through difficult problems
◦ Encourages students to provide well-reasoned
◦ Allows instructor to see where misunderstandings
are occurring
Longer term benefits
◦ Develops critical thinking, logic, & writing skills
◦ Allows for deeper exploration of course material
◦ Helps student see the broader implications of
economic concepts
ABCD Method
◦ Developed after seeing Robert Beichner
from NCSU share the method he uses for
problem solving in physics (called GOAL)
◦ Four steps to solve econ problems
Analyze the problem
Background information
Combine to solve
Double-check & reflect
◦ Box “Why”
◦ Underline “supply”
◦ Maybe underline “upward-sloping”
◦ Supply: the relationship between price and the
quantity firms are willing to produce/sell; the
minimum price the producers will accept for each
additional unit
◦ Upward-sloping: P & Qs move in the same direction
 Box “The minimum price the producers will
accept is based on the cost of production. We
know that the cost of production rises as
quantity increases, therefore, the firm will
require a higher price as they produce more.”
 I have to be careful to explain WHY, not just
restate information the question has given.
(or some other reasonable lesson)
On the back of each ABCD handout is 1
of 5 examples; share them around so
everyone gets to see a few
Try writing an ABCD answer & rubric for
the questions you jotted down earlier
◦ Do you see any benefits to using the ABCD
◦ What problems do you foresee to using the
ABCD method?
Please feel free to contact me with
questions or to share your experiences
if you try the ABCD method.
Sarah E. Jackson
[email protected]