What are psychometric tests?

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3 508 U2 AOS2: Intelligence and personality Figure 18.1 A school psychologist gives a student a Wechsler Intelligence Scale test. This tests cognitive abilities in children and adults. What are psychometric tests? A psychometric test is a standardised measure of a selected aspect of an individual s behaviour. It is an instrument used to identify individual differences in psychological functioning among people. Psychometric tests: measure one selected aspect of an individual s psychological functioning provide a score to allow an individual to be compared with other people allow predictions to be made about an individual s future performance or behaviour are used by psychologists as part of an assessment process, either for a group of people or for individuals. Examples of psychometric tests of intelligence Intelligence tests are standardised measures of a person s general mental ability. These tests are designed to measure an individual s probable level of intelligence. There is a variety of individual tests for measuring intelligence available to psychologists. Two of the most commonly used tests are the Stanford Binet Intelligence Scales and the Wechsler Intelligence Scales. These tests are carefully designed and must be administered and scored by fully trained psychologists. Stanford Binet Intelligence Scales The Stanford Binet Intelligence Scales test was originally designed in 1905 by Alfred Binet, a French psychologist. It was later revised in 1916 by Lewis Terman, a professor of psychology at Stanford University. It has been revised several times since then, and the current version is the fifth edition. This test is designed to assess individuals according to age. A psychologist who is testing a 10-year-old child will start by asking the test questions for 9-year-olds. If the child is able to answer these questions, the psychologist then proceeds to the questions for 10-year-olds. If these are answered correctly, then the child is asked the questions for 11-year-olds and so on until the child reaches a set of age-related questions for which he or she is unable to provide answers. The psychologist then computes the intelligence quotient (IQ) score by comparing the child s scores with the norms for 10-year-olds set out in the tables provided by the test designers. (IQ scores are discussed in detail below, on page XXX.)The mean IQ for each age is 100. A child who has answered questions for children from an older age group will generally score a higher-than-average IQ score, whereas a child who was unable to answer the relevant questions for his or her age group would score a lower-than-average IQ. The most recent version of this test (SB-V) provides a single IQ score and also UNCORRECTED PAGE PROOFS provides scores for various aspects of intelligence: fluid reasoning knowledge qualitative processing visual spatial processing working memory.

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6 ch 18: Methods of measuring intelligence 511 Test types Psychometric tests can either be group tests or individual tests. In group tests, paper-and-pencil tests are given to a group of people at the same time. For example, the Differential Aptitude Test (DAT) is a test of school achievement which is often given to students in Year 10 for the purpose of course selection and vocational guidance. Individual tests are administered by a psychologist in a one-on-one situation with a client. These tests may involve paper-and-pencil tests, oral (spoken) and aural (listening) tests, as well as manipulation of objects such as blocks and puzzle pieces. Examples of individual tests include the Wechsler Intelligence Scale for Children IV (WISC-IV) and the Stanford-Binet Intelligence Scale V (SB-V). Issues in psychometric testing Psychometric tests can be quick and inexpensive ways of obtaining information about the psychological functioning of one or many people. There are, however, some drawbacks with these tests that psychologists must always consider when using them for assessment. These drawbacks can sometimes contribute to incorrect measurements of a person s true psychological functioning. The main considerations regarding psychometric testing are shown in Figure It is very important that psychometric tests are designed and carried out in a way that ensures high quality and fair measurement. To do this several areas must be dealt with: Standardisation Test conditions must be the same for all. Fairness of test design Culture and linguistic bias some tests may unintentionally favour one population more than another. Practice Some people are more experienced in sitting tests and may do better than those who are inexperienced. UNCORRECTED PAGE PROOFS Motivation Some participants are more eager to do well than others. Quality control in test design Tests must truly measure the property they have been designed to measure (validity), and they must be consistent from one test sitting to the next (reliability). Issues in psychometric testing Reliabilty A test must be consistent yielding the same scores under the same circumstances on different occasions this is referred to as the reliabilty of the test. Application of results > Tests are only one form of assessment and must not be used on their own to form an impression of a person s psychological functioning. > A test only takes a sample of a person s psychological functioning on any given day. This is similar to a blood test, which is only a sample of a person s physiological functioning at a particular time and place, where blood sugar and adrenaline levels can vary. Similarly, when sitting psychological tests an individual may be nervous, unwell, tired or distracted. These variables can influence test results from one day to the next. Validity The test measure what it intends to measure this is referred to as the validity test. Figure 18.3 Issues in psychometric testing

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12 ch 18: Methods of measuring intelligence 517 a Yuin b Wonnarua c Bundjalung d Thungutti. 11 Who is Michael O Loughlin? a an NSL player b an NRL footballer c an AFL player d an NBL player. 12 If you were playing coon-can, would you be playing: a a card game b the spoons c a children s game d a musical instrument made out of cans? 13 What are munyas? a money b scabies c head lice d swollen feet. 14 Deb Mailman is: a a postal worker b an athlete c a news reader d an actor. 15 Which colour is not on the Koori flag? a red b green c yellow d black. 16 If a wharki caught you, what would have you? a an old man b a policeman c an evil spirit d a welfare officer. 17 What would you do with a Wilcannia boomerang? a throw it b hang it on your wall c tackle it d paint it. 18 Linda Burney is: a Chairperson of ATSIC b President of NSW AECG Inc c Chairperson of NACCHO d State Member for Canterbury. 19 What organisation funds CDEPs? a AEC b DET c ASA d ATSIC 20 Where is Dodge City? a near Singleton b near Texas, Queensland c near Brewarrina d near Wallaga Lake UNCORRECTED PAGE PROOFS Other factors that influence intelligence test scores Performance on intelligence tests can be influenced by non-intellectual factors, which are things that might reduce or improve an individual s performance. These include: Physical impairment: Sight or hearing disability might prevent an examinee from performing to the best of his or her ability. Motor impairment might restrict an individual s ability to use a pencil or to manipulate blocks. Physical impairments must be taken into account by the psychologist because they have the potential for causing the examinee s true intellectual ability to be misrepresented by the scores obtained. Test anxiety or shyness: Some individuals may be shy with the examiner or very nervous about their performance on the test and this could hinder them doing their best. In this instance, obtained scores would not be truly representative of their ability. Test familiarity: Some individuals might have sat the very same test within the previous two years. If the psychologist is aware of this, then an alternative test can be used. If not, the examinee might obtain a score that is higher than he or she might have otherwise achieved. overmatter

13 518 U2 AOS2: Intelligence and personality Figure 18.7 Physical impairments can influence performance on IQ tests. IQ tests and school performance IQ tests that are formally recognised and administered by qualified psychologists can make reasonably accurate predictions about an individual s potential for learning in school, including the ability to understand, remember, follow instructions, use language, and solve problems. It must be emphasised, however, that an IQ score does not explain or predict actual school performance. It is possible for an individual with a high IQ score to perform poorly at school for various reasons; for example, sickness and absence from school, or an unsettled family or social life. It is important to remember that intelligence tests and IQs are measurements and scores, not UNCORRECTED PAGE PROOFS explanations for how students actually perform at school. Figure 18.8 Performance in tests at school can be influenced by sickness, absence from school, an unsettled family life, or personal issues with other students or friends.

14 ch 18: Methods of measuring intelligence 519 Advantages and disadvantages of intelligence tests There are advantages and disadvantages in using psychometric tests to attempt to establish the level of an individual s intellectual ability. Advantages Intelligence tests provide a standardised IQ score. They are easy, quick and cheap to administer and score. If the tests have been properly constructed, they may be more objective and fairer than an interview or face-to-face assessment. They enable individuals to be compared against other people their age. They are helpful in making predictions about academic performance. They can be useful for selection purposes for people best suited to certain tasks, careers or particular intervention, such as those with intellectual disability or giftedness. Disadvantages Intelligence tests are rarely perfect and may disadvantage individuals if they are used inappropriately. They must not be used unless there is evidence that they have strong reliability, validity, and standardised testing and scoring procedures. They do not take into account individual differences, such as nervousness, personality characteristics, experience in testing and motivation. Most intelligence tests tend to measure cognitive abilities and do not include other forms of intelligence, such as those suggested by Gardner and Sternberg or the CHC model. Intelligence tests tend to be culturally and linguistically biased. There is the potential for intelligence test results to be used to label people unfairly, either positively or negatively. UNCORRECTED PAGE PROOFS Ethical issues in intelligence testing Binet designed his original intelligence test as a means of identifying children who might need support in their education because their level of intelligence was abnormal. Therefore, his aim was to assist children in their education. Yet, during the early 1900s Binet realised that intelligence tests such as his also had the potential to be used for purposes that were different to those he had intended. His main concerns were: Intelligence tests could be incorrectly used as a way to label people. Intelligence was deemed to be genetic (inherited) by some members of the scientific community, and this could lead to discrimination against some groups of people on the basis of their genetic background. Binet s point was that intelligence tests will never provide the whole picture about an individual s general mental ability. Instead, the tests must be used in conjunction with other means for making decisions about a person s intellectual potential. History demonstrated that Binet s concerns were borne out during the twentieth century in several episodes in the United States.

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