Classroom Assessment Techniques for Teachers of Senior Science Subjects
Colin Macpherson
and Ron Pedder
Abstract
Combining school-based assessments with examination results in an attempt
to gain more valid evaluations of student abilities is not a new idea. However,
the ways in which the idea is implemented can vary from place to place.
Beginning in 1993, teachers of the three science subjects offered by the PSSC
(Pacific Senior Secondary Certificate) system - now used in five Pacific Island
countries - will be required to follow a number of rules regarding the internal,
or school-based, assessment of their students. In order to help science
teachers with some of the measurement tasks they will be expected to carry out,
the examining authority has published a teachers' guide. This article provides
some background about this move and presents sections of the guide that may
be useful to a wider range of science teachers.
Introduction
The Pacific Senior Secondary Certificate (PSSC) is unique in our part of the
world in that it is an educational accreditation system that originated in the
region, is increasingly run by regional people, and is currently used in five
Pacific-island states (Solomon Islands, Kiribati, Tonga, Vanuatu and Western
Samoa). The system is coordinated and maintained by the South Pacific Board
for Educational Assessment (SPBEA) - an organization set up, partially
financed, and governed by 10 member countries. There are nine PSSC
subjects available to students (Biology, Chemistry, Physics, Mathematics,
Geography, History, Economics, Accounting and English) who are normally
required to study five in their twelfth year of formal education.
At the end of the year, students sit for a formal examination in the subjects they
have been studying. The examinations are based on norm-referenced
measurement principles - i.e., a student's achievement is defined in terms of
her rank rather than in terms of some form of absolute standard. Some subjects
5 4
have always had an internal assessment (I.A.) component that contributes,
together with the examination score, to students' final grades. These grades
take the form of whole numbers ranging from 1 (the highest) to 9 (the lowest).
Some other subjects have the assessment of students based on the examination
alone, and others may or may not include an LA. component depending on
which country students come from. This last group of subjects includes the
sciences (Biology, Chemistry and Physics), and has long been the topic of
debate amongst those concerned with consistency of assessment from place
to place within the system.
From 1993 however, assessment of student achievement in each of the
sciences will include a newly-defined LA. component that will be used by all
participating countries. These new requirements are listed in an appendix at
the end of this article. Suffice it to say here that science teachers will be
required to submit for approval (to the SPBEA) LA. programs that follow
certain rules but also allow for a degree of independence. A common feature
of all the programs will be the emphasis placed on the assessment of skills
associated with 'practical work'. Indeed, for the first time, students of any of
the science subjects will be required to complete a minimum number of
practical activities. They will also have to write reports regarding these
activities. Teachers will be required to include their marks for some of these
reports as part of the total internal assessment of each student. For some time
there has been concern that many teachers may not have been placing the
degree of emphasis on practical activities necessary for useful and effective
science education at the senior level. The new rules then, are intended to not
only produce more broad-based assessments of student abilities but to also
influence the style of teaching taking place in many classrooms. It is, in fact,
an attempt to use the well-recognized power that assessment systems have
over what is taught and how it is taught, to improve both teaching and learning.
The designing and implementing of these programs may prove difficult for
many teachers - particularly those with little experience in classroom assess-
ment techniques that go beyond simple pen and paper tests. For this reason
the SPBEA has produced a booklet entitled "PSSC Internal Assessment in
English and the Sciences - a Teacher's Guide". Part of this guide suggests
techniques that science teachers may use in order to be more objective in their
assessment of student abilities. The rest of this article is taken from that
55
section of the guide. Rather than being an academic treatise, it uses a practical
hands-on approach aimed at science teachers. Although specifically written
for the PSSC system it may be of interest to a wider population of educators.
(Quoting from "PSSC Internal Assessment in
English and the Sciences - a Teacher's Guide")
Types of Assessment Tasks
Earlier in this guide an 'assessment task' was defined as any activity a student
had to complete that was related to the course, and which would be assessed
by the course teacher. Mention was made of two categories of such tasks -
'included' and' formative' those that will' count' towards student final scores
are the 'included' tasks. Those that are designed to help improve student
learning but are not used in determining the final I.A. score are the' formative'
tasks]. But what types of activities are available to science teachers when
designing these tasks?
Some examples are:
Quizzes (brief tests)
Pen-and-paper tests
Practical tests
Practical reports
Research projects
Experimental investigations
Assignments
Theory-based problems
Seminars
Essays
Some of these tasks can be readily carried out under strict teacher supervision
(e.g., tests), others cannot. Also, a number of such activities may be included
in the one task. For example, a student may be given a major research project
56
that will require some initial library research, some experimental investiga
tion, and a detailed report. Whatever form the LA. Tasks you design take,
ensure that in each case you:
-have a clear idea of what you expect from your students,
-have related the tasks to the prescription objectives and/or content,
-give the students a clearly written description of the task,
-prepare a marking scheme (showing marks available for each skill
area) together with the task description and also give this to students.
Using Checklists and Rating Tables for Assessment
LA. Tasks should relate to course objectives. That is, they should enable
specific skills and abilities to be assessed. These skills and abilities are often
part of the overall objectives listed in the course prescription.
When marking assignments it is easy to simply read through the work of each student
and then make a very subjective decision on the mark each assignment should receive.
Such an approach to marking is not satisfactory, especially when an assignment
contributes towards a student's LA Score. It is important that marking is objective.
Both checklists and rating tables can be used to identify specific criteria you
have regarding skills being assessed in a task, and will therefore help you to
be objective in your marking. The only difference between the two is that a
checklist simply requires you to place a tick (√) against each criterion if the
student demonstrates the required skill or to leave it blank if he or she doesn't.
A rating table, on the other hand, has a scale (i.e., a number of possible marks)
for each criterion, and requires you to make a more refined judgement about
where each student's skill or ability falls on the scale.
The design of a checklist or rating table will depend on the particular task and
the skills and abilities being assessed. The following two examples of rating
tables (figures 1 and 2 ) are based on particular objectives in the PSSC Biology
Prescription. Figure 3 is an example of a checklist.
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PRACTICAL REPORT - RATING TABLE
(This assessment is for GRAPH WORK)
Max.
Poss.
* Suitable title
1
½
-
* Labelled axes
2
1
-
* Units of axes
2
1
-
* Accurate plotting
1
-
* Clear plots
½
-
-
* Axes right way around
½
-
-
* Even Scales
1
½
-
* Neat
1
½
-
* Suitable size
½
-
-
* Correct type of graph
½
-
-
TOTAL (max 10):
COMMENTS:
Figure l:An example of a rating table that could be used to assess the
section of a practical report involving graphing skills.
(This rating table could be used, for example, to assess some of the skills
involved in 'recording and presenting data' - an objective stated in the PSSC
Biology Prescription.)
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SEMINAR - RATING TABLE
CONTENT:
LEVEL
1
2
3
4
* Range of references used
* Research relevant to topic
* Information accurate
* Examples used
COMMUNICATION:
* Clarity
* Fluency
* Formal structure
* Logical arguments
* Interesting
* Questions answered
TOTAL
Total mark ÷ 4 = mark/10
KEY:
1= unsatisfactory 3 = good
2= adequate 4 = excellent
Figure 2:An example of a rating table that could be used for assessing
student seminars.
(This rating table relates to the 'locating information' and 'communicating
orally' objectives in the Biology Prescription.)
59
Students should be shown a copy (possibly on a blackboard) of the checklist
or rating table you will be using when assessing a particular LA. Task. This
will allow them to devote their energies to those areas you think important.
Also, duplicate copies of the table can be made (each student could draw up
their own copy) and be returned, completed, to each student after the marking
process. This will show students how their total score was determined. You
can probably see how checklists and rating tables lean towards the CRM
[criterion-referenced measurement] approach to assessment discussed earlier
in this guide [but not in this article]. Although single words or phrases may
appear in the tables, these may in fact be abbreviations for more extensively
specified criteria (this, however, doesn't have to be the case).
Assessing Practical Skills
Several of the key requirements for the internal assessment of PSSC Biology,
Chemistry and Physics centre on skills necessary to carry out practical
activities that are directly related to the course as defined in the prescriptions.
Furthermore, these should be skills that cannot be easily measured during the
examination. For example, an examination question may ask students to write
a description of how to prepare a microscope slide of cockroach mandibles.
As a result, we can then determine whether a student knows in theory how to
carry out the task. This, however, is not the same as seeing whether a student
can actually prepare the slide.
The traditional examination setting does not allow for such an assessment, but
a school setting does. This is why teachers will have the responsibility of
assessing 'doing skills' of this kind (i.e., doing more than sitting at a desk
writing) and is one of the reasons for having the "practical activities"
requirement in the LA. section of the prescriptions [see the appendix].
Practical Reports
The PSSC science prescriptions attempt to ensure that at least some practical skills
will be assessed via the student practical reports (a minimum of 5 to be treated as
Included LA. Tasks) and practical tests (a minimum of one).
60
++The practical reports, composed and authored by students, should refer to
activities that typically involved the physical manipulation of equipment,
specimens, or the environment according to some predetermined procedure
(which may be designed by the student); the observation and recording of
results or behaviours or appearances; and the analysis and conclusions
resulting from these observations. Teachers should avoid simply marking all
practical reports for being complete or for having correct answers to a series
of questions. Rather, one or two skills or abilities should be identified for each
practical investigation and well constructed checklists or rating tables used to
assess these objectively. For example, an investigation in biology, chemistry
or physics which required students to gather data and use it to construct a graph
could be assessed for the skill of recording and presenting data. The rating
table shown in figure 1 could be used to assess this skill. Students should be
informed of the skill or skills which will be assessed in any practical
investigation. These practical activities must take at least one normal class
period to complete and should be a regular part of the course. The practical
test is included in the requirements because student reports, although focusing
on practical activities, do not let you see first-hand what a student has done.
A practical test, on the other hand, allows you to observe students in action.
Practical Tests
Practical tests can be used to find out if a student has really mastered particular
skills. The student is given one or more specific tasks that involve the use of
scientific equipment or the application of certain skills. The teacher then
assesses the student's level of skill either by observing the student carrying out
the task or by checking the final result.
There are many tasks that students could be given. For example:
-connecting up a particular type of electrical circuit,
-finding the focal length of a lens (or curved mirror),
-using a ticker timer,
-finding the density of a stone,
6 1
-separating pigments by means of chromatography,
-preparing and testing for hydrogen,
-carrying out a titration,
-testing an unknown solution for starch, glucose and protein,
-dissecting an insect,
-weighing a coconut,
-preparing a microscope slide of some pond slime and setting it up under
a microscope,
-designing an experiment to test a given hypothesis,
e.g., * that the volume of liquid in a coconut decreases as the
coconut gets older,
* that a fishing line is weaker if it has a knot in it,
* that pigs have set sleeping and foraging times,
* that the daily temperature changes that occur in coral sand
and soil will be similar.
(Remember: Do not include a task in a practical test unless students have
been taught the general principles related to that task. However, it would be
possible to give a student an experiment that had not previously been studied
if you were assessing the ability to follow instructions or if the student had
completed an earlier experiment that was based on the same principles.)
Practical tests are excellent for assessing practical skills and students usually
find them enjoyable and stimulating. Designing and setting up a good
practical test will take some time and careful planning. Marking the test, on
the other hand, is usually quite simple.
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The easiest practical test to design would be one where all students are given
the same practical task (e.g., one from the list above) and have a set time to
complete it. In reality such an approach is often not possible as there may not
be sufficient equipment for each student or it could be too easy for students
to see what others are doing. Such problems can be overcome by having just
a few students doing the task while the rest of the class is working unsupervised
in another room, or by taking students aside one at a time and having them
carry out a particular task while you watch and assess their performance. In
this case the rest of the class would be continuing with set work in the same
room.
With practical tests involving a single task, a checklist can be designed to
quickly assess each student. Figure 3 shows a checklist that could be used with
a practical test in biology where students are asked to prepare a microscope
slide of some pond slime, set up their slide under a microscope and focus it
on low power.
63
Slide Preparation and Microscope Use - Checklist
1
Names
* Slime spread
out
* Coverslip
present
* No water on
top of
coverslip
* No air bubbles
or few air
bubbles
* Mirror
adjusted
* No water on
stage
* Correct
magnification
* Slime in
field of
view
* In focus
TOTAL/9
Figure 3.A checklist designed to be used with a particular practical
test.
6 4
This checklist could be easily modified (e.g., if different material was being used or
if students were asked to use a stain) or extended (e.g., if they were also required to
draw a diagram of what they saw down the microscope).
Another type of practical test that overcomes the problems of limited equipment and
collusion between students but can still be sat by a whole class, is the 'station-type'
practical test. In this type of test several 'stations' are set up around the room. At
each station there is an instruction card telling the student exactly what to do and all
the equipment that will be required. Each station has instructions for a different task.
The number of stations will depend on the time each task will take and the total time
available for the test. e.g., If 5 minutes is given for each task then a 1O-station test
could take 50 minutes to complete. If there were more than 10 students in the class
it would be necessary to either:
-add more stations and make the test longer,
-add more stations but reduce the time spent at each station so that the
test will still take the same time,
-set up an identical test in another room.
Station-type practical tests take time to set up but are easily controlled
by a single teacher. The following steps should be followed:
-students should be given clear instructions about the test before entering the room,
-ideally, each student should be given an answer sheet designed specifically
for the questions in the test (this will help prevent confusion and will also make
marking much easier),
-students enter the room and one student occupies each station,
-each student spends the allotted time on the task at his or her station,
-the teacher signals 'time up' and all students move to the next station,
-the test ends when all stations have been visited by each student.
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Appendix
Additions to the PSSC Physics Prescription (almost identical additions apply
in Biology and Chemistry).
Internal Assessment
1 There are a number of benefits that can result from a well-designed school-
based assessment scheme. However, the two major purposes of any PSSC
internal assessment program are to:
(i) measure subject-related skill and abilities that cannot easily be
measured by pencil-and-paper tests (e.g., certain practical skills in
science subjects, long-term research and investigative skills, etc.),
(ii) measure the same skills and abilities that the end-of-year
examination attempts to measure; the justification for this being that
repeated assessment is likely to be more accurate and fair than
assessment based on a single examination.
These should be kept in mind when designing such a program for submission
to the SPBEA.
2 The PSSC Internal Assessment will be weighted as 40% of the total
assessment. The final examination will be weighted as 60% of the total
assessment.
3 At least fifteen (15) practical activities directly related to course objectives
and content, as described in this prescription, each practical requiring at least
one normal class period to complete, must be carried out by each student.
Students must also write a report on each of these activities. This is a
prerequisite for sitting the final examination.
4 A large but undefined fraction of the PSSC Internal Assessment will be based
on skills required for successfully carrying out subject-related practical
activities that cannot easily be measured in a single, end-of-year examination.
Specifically, half (50%) of the Internal Assessment will be based on the
66
assessment of a minimum of five (5) student practical reports - the same five
for each student.
5 The remaining half (50%) of the Internal Assessment will be based on the
assessment of a minimum of five (5) assessment tasks other than the regular
practical reports. At least one of these tasks must be a practical test. The other
tasks may be, for example, further practical tests, other types of test,
assignments, research projects, seminars, etc. These tasks may also require
practical skills.
6 Although it is recognized that certain general student attitudes and behaviours
may be desirable (e.g., co-operativeness, perseverance, politeness, etc.) these
should not play any part in the PSSC Internal Assessment Program submitted
by any school. Attempts to quantify and report such qualities should be done
as a separate school activity.
7 Schools that intend to enrol students in PSSC Physics must submit a
completed "PSSC Internal Assessment Summary Form" by March 1st in
the year of enrolment. These forms will be provided by the SPBEA. Several
forms may be necessary to document a school's Internal Assessment Program.
Further information must also be attached to these forms. This information
should include details about procedures and the marking of separate assess-
ment tasks, and descriptions of intra-school moderation of internal assess-
ments if a school has more than one class following PSSC Physics.
8 Schools must supply a single mark out of 100 (i.e., 100 is the maximum
possible score) for every enrolled student - this mark being directly based on
the school's SPBEA-approved PSSC Internal Assessment Program.
9 Clear records and documentation regarding the school's approved PSSC
Internal Assessment Program must be kept. Furthermore, all student work that
has been assessed under this program (tests, essays, practical reports, projects,
etc.) must be available for verification by SPBEA officers during any one
school year.
10 Students who will be enrolled in PSSC Physics must be given a copy of the
school's PSSC Internal Assessment Program for the subject. Each student
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must also be informed of when assessment tasks are to be given, and be notified
of his or her assessment result for each task as soon as it is determined.
11 Relevant teachers and school principals will be required to sign the "PSSC
School Agreement" form to confirm that the above PSSC Internal Assess-
ment rules will be followed. Non-adherence to these rules may cause students
to be removed from PSSC enrolment in some subjects.
Note: Advice to teachers on how to design an Internal Assessment Program is
contained in the SPBEA booklet 'PSSC Internal Assessment in English and
the Sciences - a Teacher's Guide'.
References
"Assessing Form 6 Biology Practical Skills". Wellington, New Zealand:
Department of Education, 1987.
"Form 6 Biology Draft Teachers Guide -Assessment". Wellington, New
Zealand: Department of Education, 1986.
"Form 6 Biology Draft Teachers Guide -Skills". Wellington, New Zealand:
Department of Education, 1986.
Gronlund, N.E. and Linn, R.L. "Measurement and Evaluation in Teaching".
New York: Macmillan Publishing Co. Inc., 1990.
Macpherson, C.R. "PSSC Internal Assessment in English and the Sciences -
a Teacher's Guide". Suva, Fiji: SPBEA, 1992.
Popham, W.J. "Criterion-Referenced Measurement". New Jersey: Prentice-
Hall Inc., 1978.
Rowley, G.L. and Macpherson, C.R. "Criterion-referenced measurement", in
SET: Research Information for Teachers (ACER & NZCER), 1983, 1, item
11.
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