“Clickers”: Electronic
Audience Feedback in the classroom.
Michael Dubson,
Physics Dept
(last updated
Since the Spring
of ’02, the Physics and Astronomy Departments at CU have been using an
electronic audience feedback system in several large freshmen classes. During lecture, students answer
multiple-choice questions (“Concept tests”) with personal electronic
transmitters. The system records how
each individual student voted, so individual students
scores are maintained. The system we use is manufactured by an Arkansas-based
company called H‑ITT(Hyper-Interactive Teaching Technology); their web
site is http://www.h-itt.com/
Here’s how the system works: Students purchase a small infrared
transmitter, called a “clicker”, at the CU bookstore for $29 each. The bookstore will buy back clickers for
half-price at the end of the semester. Clickers, which are the size of a magic
marker, take two AA batteries. Each
clicker has a unique ID number stamped on it, and students register their
clicker ID along with their name and student ID at a local web site, which is
maintained by the Physics Dept: http://capa.colorado.edu/cgi‑bin/RegisterAFS
This web site produces a list of students
and their clicker IDs, in a format suitable for use with the H-ITT software.
The lecture hall is wired up with
receivers arrayed around the room. For
votes to be recorded quickly, you need one receiver for every 25 students. Each receiver costs $180, so, for instance, a
300-seat lecture hall requires 12 receivers at a total cost of $2160. All
software is free and can be downloaded at anytime from www.h‑itt.com. If you have a small class of 50 students or
less, you might consider a portable system: bring in one or two receivers into
the classroom, set them up on tripods, and hook to a laptop.
Other costs include :
1) PC and cart (about $2000). The receivers are daisy-chained and the last
receiver in the chain is plugged into a PC, which controls vote-collecting,
maintains records, etc.
2) LCD projector ( $1500) We strongly recommend that you use separate
projectors for display of the clicker statistics and for course content. As explained below, you need to display a
clicker status screen continuously while questions are displayed.
3) Receiver installation, cables, etc.
(maybe $300 worth of cables, connectors, etc. for large lecture hall -- labor not
included).
4) Your time! Plan on an extra 5-minutes
prior to the start of each lecture to set up/test the system. The software is very intuitive, but it is
powerful and flexible and takes a few days to get thoroughly used to. Another
grade column in your spreadsheet (class-participation) requires organization
and planning. Dealing with occasional student complaints/claims that the system
is faulty. All this takes time — not a
lot, but it is non-negligible. Some
instructors have assigned one of their TA’s to be fully responsible for
operation and maintenance of the system.
During
a typical 50-minute lecture, students are asked
of the clicker ID (it can also be
set to display the student’s initials). Cells always have the same color and
position in the matrix, so that a student quickly learns that she is the “green
cell in the lower right: 050”. When a student sees her cell appear, she knows
for certain that her vote has been recorded.
When
everyone has voted, the instructor closes the vote and has the option of
showing the class a histogram of the results.
After
class, a versatile grade-keeping program allows the instructor to maintain
grades and ship the results to excel. My
default grading scheme is this: 3 points
for a correct answer; 1 point for a wrong answer; zero points for no answer (so
attendance is rewarded). A student’s
clicker points are used to replace up to 10% of the exam score, if his average
clicker score exceeds his exam average -- hence clickers are not mandatory in
my class – a student who does very well on exams is not penalized for failing
to use the clicker)
Are
clickers a good thing? Use of clickers
has a strong positive effect on attendance.
In Phys2020, the first course in which clickers were used, average
lecture attendance went from 65% (pre-clicker use) to 92% (post-clicker
use). Student sentiment is largely
positive. In anonymous surveys, students complain about the cost of clickers,
but overwhelmingly approve of their use and want the clicker points to count a
larger fraction of the course grade.
Most important, in my view, clickers have had a strong effect on the
level of student engagement.
Prior to the use of clickers, I used
colored cards to get audience feedback.
Every student had 5 different colored cards, and would vote on Concept
Tests by holding up the correct card.
This would give me a quick, semi-quantitative idea of the level of
student understanding, but nothing was recorded. At the beginning of every semester, students
were intrigued by this novel system and would vote enthusiastically. However, within a few weeks, I always
encountered “the fade”: the novelty wore off and students would stop voting
unless I constantly cajoled them to participate. With clickers, there is no vote fade;
students vote all the time.
Miscellaneous
comments:
·
At
present, 9 lecture halls at CU have clicker receivers installed. Three rooms in
Duane Physics (G1B20, G1B30, and G125) , Ramaley C250,
Crystol Chemistry 140 and 142, Hale 270, and two
rooms in Engineering (ECCR105, and ITLL1B50).
These installations have been funded by a combination of student fees,
FTEP funds, and ITS support.
·
Unlike
colored cards, clickers cannot be used to get an “instant” vote. With 300 students, it takes a minimum of 45
seconds to get all the votes in. The
problem is that rapid voting causes a traffic jam: if two clickers are fired at
the same receiver simultaneously (within 0.1 seconds), neither vote is recorded.
Hence the importance of a status screen showing
students when their vote has been recorded.
Traffic jams don’t occur if the student needs a minute to think about
the question before answering. But you
can’t ask a question like “Who saw Star Trek last night?”.
·
The
clickers are cheap and not very robust, but they are now much more reliable
than they were when we first started in Spring of
’02. At present, perhaps 1 in 100
clickers will be defective. When a
student reports a dead clicker, it is usually just dead batteries. Fresh batteries easily last one semester, but
not two.
Some Physics Concept tests:
Test your transmitter with this free
question = full credit for any answer.
What is the cost to put a one-pound (1
lb) payload into orbit with the space shuttle?
B) $500
C) $2000
D) $8000
E) $25,000
CT20-4. Brass
has a positive coefficient of thermal expansion. A ring (annulus) of brass is
heated. Does the hole in the middle of
the ring get larger or smaller?
A: larger B:
smaller C: stays the
same
Use of
Clickers in Physics 1020, Physics of Everyday Life.
Carl
Wieman and Kathy Perkins - CU Dept of Physics
Phys1020 is the 2nd semester
of a 2-semester introductory physics sequence, aimed at non-science majors. It
is a “physics for poets” course. We used clickers in this course in the spring
of 2003.
Types of questions.
In
this class the clickers are used for a variety of purposes, some of which are
somewhat different than discussed by Dubson in the note above.
1.
2.
Confronting known misconceptions.
Students are asked questions where it is known most of them have some
basic misconception and will give the incorrect answer. There is then follow-up discussion or
experiments and questions exploring the correct answer and the source of their
misconception.
3. Predicting results of in-class
experiments/demonstrations. Before any
demonstration is carried out, students are asked to predict what will happen.
Then they see the results and we discuss why it came out that way, and, where
appropriate, why their predictions were wrong.
4. Concept questions of the sort
discussed by Mazur, although our questions are nearly always less abstract and
more closely connected to real world situations.
5. Testing understanding of material that
has been covered. After a topic or
subtopic has been covered, questions are asked that check the student’s level
of understanding before proceeding. This
can include simple quantitative questions.
Types of clicker-enhanced student collaboration.
We found that the interaction between
students was considerably enhanced when we assigned them seats and made each
student a member of a 3 person group seated together. After many of the questions, particularly
those where there was a large spread in answers submitted, the students would
be told to talk to their group members and come up with a consensus vote. This assignment of seats and groups and
requirement of consensus answers substantially increased the level of
interaction over the standard unstructured peer instruction, particularly by
the less interactive students.
How
clickers were included in grading.
Most clicker questions are not graded. Students in class and using clickers to
answer questions receive 3 points/class.
Occasionally one of those points will depend on whether or not they
correctly answered a specific question, usually one late in the class that
anyone paying attention gets correct, which is usually nearly all of the
students. Approximately once every 1.5
weeks there is a 3-question graded quiz on the assigned reading that counts for
3 points. Over the course of the term,
the clicker points make up a bit over 20% of the total points possible.
Indications of success.
1. The class is dramatically more
interactive with a large fraction of the class (10-15 out of 45) asking
questions during a class period and the level of the questions is dramatically
higher. For example, they often are
about extensions of the material to applications not covered during class,
anticipating aspects of the topic to be covered later in the class, or asking
about outcome/suggesting of additional experiments to be done with the
interactive lecture demonstrations. A
large fraction (20-40 per cent) of the typical class period is spent discussing
such student questions.
2. Attendance is typically about 85%.
This is clearly much higher, although pre-clicker numbers are not known.
3. The students rate the “lecture” as
making a large contribution to their learning.
This is now among the highest rated elements in the class in terms of
their assessment of
contribution to their learning, whereas with more traditional
lectures it ranked lowest.
4. Overall learning by a variety of
measures is higher that before clickers were used, but several changes in
addition to use of clickers were made, so it is impossible to distinguish what
fraction of this gain was due solely to the clickers.
5. There was dramatically higher
retention of information that was presented in the form of a clicker question
and its answer. As a baseline, clicker
questions were asked on non-obvious material previously stated verbally in
class. Typically, 10% of the students
would answer such questions correctly in spite of having been directly told the
answer approximately 15 minutes earlier.
In contrast, several times clicker questions on particularly difficult
topics (where most of the students had at first answered incorrectly) were
repeated in subsequent classes two days later.
Virtually everyone remembered that the question had been asked
previously, and approximately 90% (which could well have been 100% of the
students who had attended the previous class) then answered the question
correctly.