construction of Inventory

                                                    INVENTORY

INTRODUCTION 

An inventory is a criterion - referenced test designed to help determine whether, a student has an accurate working knowledge of a specific set of concepts.

The aims of the research include ascertaining,

1. The range of what individuals think a particular question is asking.

2. The most common responses to the question.

Concept inventories are evaluated to ensure test validity and reliability. Concept inventory are educational related diagnostic tests.

TYPES OF INVENTORIES

Mainly 2 types of inventories,

            1. Interest Inventories.

            2. Personality Inventories.

INTEREST INVENTORIES

                         Interest inventories attempts to yield a measure of the types of activities that an individual has a tendency to like and to choose. One kind of instrument has compared the subjects pattern of interest to the interest patterns of successful practitioners in a number of vocational fields.A distinctive pattern has been discovered to be characteristic of each field. The assumption is that an individual is happiest and most successful working in a field most like his or her own measured profile of interest. Another inventory is based on the correlation between a number of activities from the areas of school, recreation and work. These related activities have been identified by careful analysis with mechanical, computational, scientific, persuasive, artistic, literary, musical, social services and clerical areas of interest. By sorting the subject stated likes and dislikes into various interest areas, a percentile score for each area is obtained. It is then assumed that the subject will find his or her area of greatest interest where the percentile scores are relatively high. Interest blanks or inventories are examples of self report instruments in which individuals note their own likes and dislikes. These self report instruments are really standardised interviews in which the subjects, through introspection, indicates feelings that may be interpreted in terms of what is known about interest patterns.

PERSONALITY INVENTORIES

                             Personality scales are usually self-report instruments. The individual checks responses to certain questions or statements. These instruments yield scores which are assumed or have been shown to measure certain personality traits or tendencies. Because of individuals inability or unwillingness to report their own reactions accurately or objectively, these instruments may be of limited value. Part of this limitations may be due to the inadequate theories of personality upon which some of these inventories have been based. At best, they provide data that are useful in suggesting the need for further analysis. Some have reasonable empirical validity with particular groups of individuals but prove to be invalid when applied to others. For example, one personality inventory has proven valuable in yielding scores that correlate highly with the diagnosis of psychiatrists in clinical situations. But when applied to college students, its diagnostic value has proved disappointing.

                                            The development of instruments of personality description and measurement is relatively recent, and it is likely that continued research in this important area will yield better theories of personality and better instruments for describing and measuring its various aspects. The Mooney problem Checklist [1941] is an inventory to be used by students in reporting their own problems of adjustment. The subjects are asked to indicate on the checklist the things that trouble them. From a list of these items, classified into different categories, a picture of the students problems, from their own viewpoint, is drawn. Although the most useful interpretation may result from an item analysis of personal problems, the device does yield a quantitative score which may indicate the degree of difficulty that students feel they are experiencing in their adjustments. This instrument has been used as a research device to identity and describe the nature of the problems facing individuals and groups of individuals in a school. The tendency to withhold embarrassing responses and to express those that are socially acceptable, emotional involvement of individuals with their own problems, lack of insight - all these limit the effectiveness of personal and social - adjustment scales. Some psychologists believe that the projective type of instrument offers greater promise, for these devices attempt to disguise their purpose so completely that the subject doesn't know how to appear in the best light. 

STEPS IN THE CONSTRUCTION AND STANDARDIZATION OF INVENTORY

Standardised tests are carefully constructed tests with a uniform procedure of scoring, administering and interpreting the test results. They consist of items of high quality. The items are pretested and selected on the basis of difficulty value, discrimination power, and relationship to clearly defined objectives in behavioural terms. Any person can administer the test as the directions for administering, time -limits and scores are given. These are norm-based tests. Norms are age, grade, sex etc. Reliability and validity of a test are established beforehand. A manual is supplied which explains purposes and uses of the test.

Steps for construction of a Standardised inventory

Planning the test.

Preparing the test.

Try out of the test.

Reliability of the final test.

Validity of the final test.

Preparation of norms for the final test.

Preparation of manual and reproduction of test.

1. Planning  For standardized test a systematic and satisfactory planning is necessary. For this test constructor should carefully fix up the objectives of the test. He should determine the nature of the content or topics and item types like  long answer, short answer, very- short answer type and the types of instructions  like  knowledge, understanding, application, skill have  to be included. A Blue-print should be prepared. The method of sampling, a detailed arrangement for the preliminary administration and the final administration should be determined. A probable length of test, number of questions and time limit of test completion should also be determined. A clear cut instruction for test scoring and its administration procedure should also be determined.

2. Writing the items of the test-

Writing the items of the test is a creative art. It depends upon the item writers intuition, imagination, experience and practice.  Requirements of writing the items are-

a. Complete   mastery over the subject-matter .In order to write correct items test constructer must be fully acquainted with all facts , fallacies, principles and misconceptions of the subject- matter.

b.                    Test writer must be aware of the ability and intelligence level of the persons for whom the test is meant.

c. The item writer must have a large vocabulary so that confusion in writing items may be avoided. The vocabulary used in the items should be simple enough to be understood by all.

d.           After test items are written they must be arranged properly and assembled into a test. Items should be arranged from easy to difficult.

e.Test constructer should give clear cut instruction about the purpose of test, time limit, procedure of recording the answers.

f.   After writing down the items, they must be submitted to a group of experts of language, subject.

3.Preliminary Administration-

After the modification of items according to suggestions of experts the test is ready for experimental try out to find out the major weaknesses and inadequacies of the item .It helps in finding out the ambiguous items, non functioning distractors in multiple-choice questions, very difficult or very easy items. It also helps in determining the reasonable time limit, number of items to be included in the final test, to avoid overlapping and identifying any vagueness in the instructions.

Try-out is done in three stages-

1)          Preliminary try-out-

 It is done individually to improve and modify the language difficulty and ambiguity of items , it is done on around100 individuals and workability of items are observed so that item can be modified.

b)The proper try-out-

It is done on around 400 individuals.Its sample should be similar to those for whom the test is intended.the purpose of this try out is to select good items for the test and reject the poor items. This step includes two activities-

1.Item analysis  A test should neither be too easy nor too difficult, each item should discriminate validity among high and low achievers.The procedure used to judge the quality of an item is called item- analysis.it includes following steps-

.The test paper should be arranged from highest to lowest score.

.27%test papers from highest 27% from lowest end will be selected.

.Then the number of pupils in the upper and lower group who selected each alternative for each test  item.

After item analysis only good items with appropriate difficulty level and satisfactory discriminating power are retained and form the final test. Desired numbers of items are selected according to blue print and arranged in order of difficulty in the final draft. Time limit is set.

c) Final try-out 

Final try-out is done on large sample of individuals for estimating the reliability and validity of the test. This final try out indicates how effective the test really will be when it would be administered on the sample for which it really intended.

4. Reliability of the test-

When test is finally composed, the final test is again administered on a fresh sample in order to compute the reliability coefficient. This time also sample should not be less than 100.Reliability is calculated through Test-retest method, split-half method and the equivalent -form method. Reliability shows the consistency of test scores.

5. Validity of the final test-

Validity refers what the test measures and how well it measures. If a test measures a trait that it intends to measure well then the test can be said valid one.It is correlation of test with some outside independent criterion.

6. Norms of the final test-

Test constructor also prepares norms of the test. Norms are defined as average performance. They are prepared to meaningfully interpret the scores obtained on the test for. The obtained scores on test themselves convey no meaning regarding the ability or trait being measured. But when these are compared with norms, a meaningful inference can be immediately drawn. The norms may be age norms, grade norms etc. Similar norms cannot be used for all tests.

7. Preparation of manual and reproduction of the test-

Preparation of manual is the last step in test construction in which psychometric properties of the test norms and references are reported. It gives a clear indication regarding the procedures of the test administration, the scoring methods and time limits. It also includes instructions regarding the test.

 Standardized test assesses the rate of development of student's ability. It helps in diagnosing the learning difficulties of the students. It also helps the teacher to assess the effectiveness of his teaching and school instructional programme.