Characteristic of a Good Test
Predictive validity is concerned with the test score as a function to score the performance at certain time. It means that
Constructive validity is an addition to measure the validity if three of measurement above is not ample to be measured.
b. Reliability Reliability refers to the consistency of the test scores in which a test
measures the same thing all the time. In other words, the reliability of a test refers to its consistency in which it yields the same rank for an individual taking
the test for several time. To have confidence in a measuring instrument, we would need to be assured, for example, that approximately the same result would
be obtained 1 if we tested a group on Tuesday instead of Monday. 2 if we gave two parallel forms of the test to the same group on Monday and Tuesday.
3 if we scored particular tets on Tuesday and Monday. 4 if two or more scorers scored the test independently. It is clear from the foregoing that two
somewhat different types of consistency or reability are involved: reability of the test itself, and reability of the scoring of test. The writer concludes test is reliable
if it consistently yields the same, or nearly the same rating over repeated administration.
According to Wilmar Tinambunan, “there are several ways of estimating the reliability of a test. The three basic methods and the type of information each
provides are as follow:
1 Test-retest method, which indicates the stability of test scores over some given period of time.
It means that the simplest technique would be retest the same individuals with the same test. If the results of two administrations were highly
corrected. We would assume that the test had temporal stability. If the time interval between two testing is relatively short. The examiners memories of
their previous responses will make their two performances spuriously consistent and thus lead to over estimate of test reability. On the other hand,
if the interval is so long as to menimaze the memory factor, the examiners’ proficiency may have undergone a genuine change, producing different
responses to the same items, and thus the test reability could not underestimated.
2 Equivalent-forms method, which indicates the consistency of test scores over different forms of the test.
It means the second method of computing reability is with the use of alternate or parallel forms. That is, with different versions of the same test
which are equvalent in length, difficulty, time limit, format, and other such aspects, where equvalent forms of a test exist, reliability can be increased by
lenghtening the test provided always that the additional material is similar in quality and difficulty to the original. But the satisfactory reliability could
be obtain only by lenghtening the test beyond all resonable limits, it would obviously be wiser to revise the material or choose another test type. this
method is probably the best, but even here practice effect, through reduced, will not be entirely eliminated.
3 Internal consistency method, which indicates the consistency of test scores over different parts of the test.”
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It means A third method for estimating the reability of a test consist in giving a single administration of one form of
the test, and then, by dividing the items into two halves usually by separating the ood and even numbers item obtaining two scores for each
individual by such ‗split half procedures’ two forms the results of which may be compared to provide a measure of the adequency of the sampling. If
36
Tinambunan, op. cit., p. 15.
test scoring is done by two or more raters, the reliability of their evaluations can easily be checked by comparing the scores they give foir the same
students response. Both validity and reliability have aims:
“To ensure that a point has been understood so that further teaching and learning can be proceed, to
review material studied over several previous weeks in order to prepare students for a formal examination and to familiriarise students with
particular types of test format. ”
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Finally, it can be concluded that reliability refers to the purely and simply to the precision with which the test
measures. No matter how high the reliability quotient. It is by no means a guarantee that the test measure what the test wants to measure. Data
concering what the test measures must be sought from some source outside the statistics of the test itself.
c. Practicality After validity and reliability, the writer wrote about as a good instrument,
and the writer that a test may have covered two particular things. It is validity and reliability, but, the teacher or someone who makes the test should consider
in its practical matters. In the implementation of classroom test, some of the basic problem in testing such as how much paper it needed? Is it time
consuming? Is it costly how much does the cost? What about the place, etc.
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The context for the implementation of the test must be effective and efficient. Thus, it must be practicable. A thrid characteristics of a good test is its
practicality. A test may be highly reable and valid instrument but still be beyond our means or facilities. Thus in the preparation of a new test or the
adaption of an existing one, we must keep in mind a number of every practical consideration such as economy and ease at administering and scoring.
1. Economy
37
Allison, op. cit., p. 85.
38
Arifin, op. cit., p. 264.
As most educational administrations are very well aware, testing can be expensive. If a standart test is used, writer and reader into account the cost per
copy, and whether or not the text books are reusable. Again. It should be determined whether several administrations and scorers will be needed for the
most personnel who must be involved in scoring a test. The more costly the process becomes.
2. Ease at administeration and scoring Other considerable of the practicality involve the ease which the test can be
administered. A full, clear direction provides the test administration can perform his task quickly and effectively. It
is supported by Suharsimi: “a test is categorized as high practicality if the test is practice and easy in
administration. ”
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A test is practicable if it doesn’t have a problem in its implementation
Steps in Test construction and administration
According to Louis in Measurement and Evaluation in the Schools, “there
are some steps in constructing and administering of test. The followings are: 1.
“Get ready” stage a. put the instructional material that is related to the test safely
b. Make a guidelines related to the aims of test that will be measured
2. “Get set” stage
a. Think over the type of test that will be used and the format of the test.
b. Arrage the preliminary study related to the items that will be used.
c. Consider the time will be needed to do the test. d. Examine and check test items more than three times after writing
the prilimenary draft.
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Arikunto, op. cit., p. 62.
e. Organize the test items. Count the total of difficulty item in test. Give the easiest questions first to build the poorer students
confidence, interest and motivation in doing the test. f. Give a clear instructions in test.
g. Determine how to score the test. 3.
“Go” stage a. Consistent related to the time consuming in test.
b. Having a good classroom management while the students do testing.
c. Administration the test orderly. ”
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To wrap up those idea above the practicality is one of factors that have to be considered in administering the test. And based on the explanation above the
validity, reliablity and practicality are the characteristics of a good test. Meanwhile, there is another particular thing that must be considered by teacher
and test constructor, the thing is the quality of the test items. The method to know the quality of test items is called Item Analysis.