Testing has always been an integral part of the educational system
since its inception. The concept (testing) can be viewed as a set of
tasks presented to a person, the performance of which depends on the
possession of a particular body of knowledge and skill. The emphasis
being laid on continuous assessment in Nigeria’s educational system has
therefore given a boost to the testing system in our educational
institutions. The National Policy on Education (2004) emphasizes the
importance of continuous assessment by stating that “Educational
Assessment and Evaluation will be liberalized by basing them in whole
or in part on continuous assessment of the progress of the
individual”. This implies that teachers should assess both the entry
and terminal behaviour of the students in the subject being taught as
this will reveal the progress made by the individual student during the
course.
Continuous assessment has been presented as a revolutionary
approach to assessment (Yoloye, 1984), (Firth and Macintosh, 1984) and
(Ughanadu, 1994). They claim that, continuous assessment is a more
valid form of assessment than conventional examination or traditional
assessment method. The superiority of continuous assessment is based
on the fact that, continuous assessment can sample a much wider range
of skills and abilities inherent in a course of study. Continuous
assessment in many respects offers a challenge to both the learner and
the teacher of science.
A Federal Ministry of Education Handbook (1980) portrays
continuous assessment as a method of finding out what the students have
gained from the learning experiences with respect to knowledge,
thinking, reasoning, character development, industry, etc. Science
subjects and chemistry in particular, like many of the educational
disciplines, provide unique opportunities for the application of
continuous assessment. There are three major areas (components) of any
science subject which lend themselves to assessment: cognitive
(theoretical) aspects; psychomotor (manipulative) aspects and affective
(attitude) aspects.
With the advent of continuous assessment, there has been an
increasing need of classroom teachers to prepare and administer tests
in order to obtain certain vital information about what has been done
during the teaching – learning process. In this regard therefore,
testing can be used as a teaching instrument and as an instrument of
assessment. These purposes are essential in the teaching of
chemistry. When used as a teaching instrument, the outcome of a
testing exercise provides a quick feedback on what learning has taken
place in the classroom. As an aid to teaching, testing finds out
problems with teaching strategies adopted, or detects weaknesses and
strengths of the students taught. In this instance, testing serves a
diagnostic function.
As an instrument of assessment, a test measures achievement,
predicts performances and aids in selection exercises. Testing
therefore, provides useful information for decision making about
students, teachers and the programme.
For ascertaining the gains of the instruction process, achievement
tests are administered by teachers. These according to Ughamadu,
Onwuegbu and Osunde (1991) are tests that measure the extent to which a
person has acquired certain information, mastered certain skills,
usually as a result of specific instruction. In most of our schools,
teachers set and administer most of these tests in the bid to find out
how much their students have gained in the course of their
instructions. These tests are in most cases not scrutinized for
validity and reliability which are the most incompromisable requirements
for a good test. According to Osunde (2000) “Teacher – made tests
are generally deficient in numerous ways. The most common fault is
related to ineffective communication”.