qualities of good measuring instrument

1. Qualities of a
Good Measuring
Instrument

2. The development of test of any
kind always requires the careful
consideration of the qualities of good
measuring instruments. Particularly,
for any test to be effectively
developed, it should carry the
qualities of a good test.
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3. Validity
Validity is the most important quality of a
good measuring instrument. It refers to the
degree to which a test measures what it
intends to measure . It is the usefulness of the
test for a given measure. A valid test is always
reliable.
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4. The legibility of the handwriting , skills in
writing, and use of sentence structures are
some factors that affect the validity of the test.
What else affect/s the validity of the test?
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5. Methods of Validating a Test
There are at least four methods by which
we can establish the validity of a given test.
These are:
1. by judgment of competent teachers, usually
three or more experts in the field;
2. by correlating the result of the test scores
against an outside valid criterion;
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6. 3. by computation of the percentage of
students who got the answer right both in the
upper and the lower groups; and
4. by factor analysis.
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7. Reliability
Reliability is the second important quality
of a good measuring instrument. It refers to
consistency and accuracy of test results. If the
test measures exactly the same degree each
time it is administered, the test is said to have
high reliability. A test to be reliable should
yield essentially the same scores when
administered twice to the same group of
students. 7

8. Ponder this!
Increasing its length or items may
raise the reliability of the test. Clear and
concise directions would also increase
the reliability of the test.
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9. Methods of Determining Reliability
There are at least three methods by which
we can establish the reliability of a given test.
These are:
1. by correlating the results of the test which
was administered twice to the same students
at different time;
2. by comparing the results of the test with
those of a reliable test; and 9

10. 3. by correlating the results of the test which
was administered once to the students. In the
case of correlation of the test conducted once,
the results are divided or broken into two sets,
which may be done on the basis of certain
criterion.
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11. Objectivity
It refers to the degree to which personal
judgment is eliminated in the scoring of the
test. Therefore, objectivity in the test requires
that the personal opinion of the teachers does
not affect the score of an individual student.
The test should be such that different
teachers can similarly score the tests and
arrive at the same scores.
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12. In other words, the more objective the
test, the greater is its reliability.
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13. Administrability
It refers to the ability of the test to be
administered easily. To facilitate
administration of the test, instructions should
be clear, simple, and directions should be
given to the students, to the proctors, and to
the scorer(s).
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14. Scorability
It is the quality wherein the test can be
scored in a simplest way and at a quickest
possible time.
To facilitate scoring of the test, directions
should be clear and separate answer sheet
must be provided.
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15. Comprehensiveness
It refers to the degree to which a test
contains a fairly wide sampling of items to
determine the objectives or abilities so that
the resulting scores are representatives of the
relative total performance in the areas
measured.
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16. Interpretability
It is the quality of the test in which the test
results can be readily, easily, and properly
interpreted.
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17. Economy
It refers to the cheapest way of giving
the test. Tests should be economical and
it should not be a burden on the part of
the teachers.
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