Presentation on theme: "NATURE AND USES OF PSYCHOLOGICAL TESTS. What is testing? Why do we have so many tests? What are the pros and cons to testing? How can we use testing to."— Presentation transcript:
NATURE AND USES OF PSYCHOLOGICAL TESTS
What is testing? Why do we have so many tests? What are the pros and cons to testing? How can we use testing to improve...? What types of tests do we take?
THE CONSEQUENCE OF TESTING The results of psychological tests can change individuals lives in profound ways.
DEFINITION OF A TEST A test is a standardized procedure for sampling behavior and describing it with categories or scores.
DEFINITION OF A TEST (Cont.) Although different tests have different formats and applications, most tests have defining features/characteristics: Standardized procedure Behavior sample Scores or categories Norms or standards Prediction of nontest behavior
Test vs. Assessment A test is also different from an assessment Assessment refers to the entire process of collating information about individuals and subsequently using it to make predictions Tests represent only one source of information within the assessment process e.g. spelling is one aspect of writing, and so to assess it we would use a spelling test. Whereas to gauge up someones general writing ability we would have to assess the entire process (spelling, style, grammar, punctuation etc.)
Psychological Testing A psychological test is a standardized measure of a sample of a persons behavior that is used to measure the individual differences that exist among people.
Psychological Testing All psychological tests have one characteristic that makes them both fascinating and remarkably practical – they try to make it possible to find out a great deal about a person in a very short period of time.
Psychological Testing Tests can be useful in predicting how well a person might do in a particular career; in assessing ones individuals desires, interests, and attitudes; and in revealing psychological problems. These tests can also show how an individual compares to others. These tests can also show how an individual compares to others. In some cases, tests can even be used to predict future behavior (though these are very controversial.)
Psychological Testing There are also some dangers to testing. One of these dangers is that we tend to forget that tests are merely tools for measuring and predicting human behavior. In some cases, society starts to think of these tests (such as IQ tests), are the FINAL fact, but nothing could be further from the truth.
Types of Psychometric Tests Two types of psychological tests are used by personnel selection practitioners: Tests of cognitive ability Cognitive assessment tests attempt to measure an individuals ability to process information from their environment Tests of personality measures Personality measures are more concerned with people's dispositions to behave in certain ways in certain situations
Different Categories of Psychometric Tests There are three categories of psychometric tests in use by psychologists: Normative tests – most psychometric tests where data exists which tell us the range of scores expected from the population under consideration e.g. IQ scores Criterion referenced tests – tests commonly used in education where a candidate has to meet some pre- arranged standard. Idiographic tests – tests used in therapy to observe an individuals progress over time
Applications of Personality Tests Criminal psychologists might employ questionnaires to measure impulsivity and its relation to crime Health psychologists might measure peoples optimism in relation to their response to cancer diagnosis Occupational psychologists often employ personality tests to predict job performance and job suitability e.g. Furnham (1992) reported that workers with high negative affect tend to be less productive and have less job satisfaction etc.
Standardization Tests must be standardized. Standardization refers to two things. First, standardized tests must be administered and scored the same way every time.
Establishing Norms Once a test result is obtained, the examiner must translate the score into something useful. Suppose you score a 32 out of 50 on a test…What does that score mean? Well, if it is a reliable test, it means that you should be able to understand a certain amount of information on every test, regardless of the way in which it is written. In other words, this score should predict how you will perform at a given level. In other words, this score should predict how you will perform at a given level.
Establishing Norms When psychologists design a test to be used in a variety of settings, they usually set up a scale for comparison by establishing norms. This is usually done by transforming raw test scores into a percentile system. What is a percentile system? Percentile System: Ranking of test scores that indicates the ratio of scores lower and higher than a given score. In other words, you are all ranked from highest to lowest…Congratulations.
Establishing Norms In order to make comparisons, tests are first given to a large number of people in a sample group – lets say 6 th graders or army privates. Percentiles are then established on the basis of the scores that these people receive. (so, in other words, tests get harder as more people take them.) These percentiles are called norms. Norms: Standard of comparison for test results developed by giving the test to large, well-defined, groups of people.
Establishing Norms Your percentile on an aptitude test, such as Scholastic Assessment Tests (SAT), reflects your standing among people of your age and grade who have taken these exams. Though, you should remember that norms are not standards, they merely represent what the majority of a given group will do. Word…
Test Reliability The ability of a test to give the same results under similar conditions. There are 3 basic ways of determining a tests reliability: 1. Test-Retest Reliability: If a person retakes the test or takes a similar test within a short time after the first testing, does he or she receive approximately the same score? 2. Interscorer Reliability: Does the test yield the same results when scored at different times by different people? 3. Split-Half Reliability: Randomly dividing the test items in half and scoring each half separately. The two scores should be approximately the same.
Test Validity Any test may be reliable but still not valid. Validity: The ability of a test to measure what it is intended to measure. For example; a test that consists primarily of Spanish vocabulary lists will not measure ability for engineering. A history test will not measure general learning ability. A test you take in physical education will not measure your ability to do math, etc…
Test Validity Determining the validity of a test is more complex than assessing its reliability. One of the main methods for measuring validity is to find out how well a test predicts performance – Predictive validity. For example; a group of psychologists design a test to measure management ability. They ask questions about management systems, attitudes towards employees, and other relevant information. Will the people who score high on the test really make good managers?
Controlling the use of Psychological Tests Ensure that the test is given by a qualified examiner and that the scores are properly used To prevent general familiarity with the test content which would invalidate the test
Controlling the use of Psychological Tests cont.. Qualified Examiner Selection of test Administration and scoring Interpretation of scores Role of Test User Test scores are used as source of information in reaching practical decisions Users are teachers, counselors, adminis Security of Test Content and Communication of Test Information
View from test takers perspective Test Anxiety – response was stimulated by ready visibility and its clearly apparent detrimental effects on performance School achievements and intelligent test scores yielded significant negative correlations It appears likely that the relation between the anxiety and test performance is non linear, a large amt of anxiety is beneficial while large amount is detrimental
Problems with Psychometric Tests Social Desirability – when faced with a psychometric test many people feel they are being judged and so alter their answers accordingly People might engage in social desirability for two reasons: Self-deception – individuals are overly optimistic in their perceptions of their own positive personality features and play down their perceived negative aspects Impression management – individuals try to appear nice because they fear social disapproval
Mood and Environmental Influence Mood does seem to play a part in how people go about performing in tests, especially those concerning personality people in a good mood might answer the questionnaire completely differently than if they were in a bad mood Features of the environment (noise, heat & light) might also have an impact on our moods and our cognitive abilities Hancock (1986) has shown that high temperature has a significant negative effect on vigilance, attention, memory and reaction time
Ecological Validity Research that lacks ecological validity focuses on what an individual can do in a research environment instead of what they are usually doing in their everyday lives If a test is not relevant to an individuals lifestyle an individual probably will not perform well at it This might be due to a lack of motivation or lack of relevant experience with the type of problem set than any lack of intellectual capability
Cultural Bias A contentious issue in the field of psychometric testing is the possibility of bias in such tests against members of ethnic subgroups of the population e.g. newly arrived immigrants will have difficulty with an intelligence test which asks them to name past leaders of the country to which they have recently immigrated At the present time most standardised psychometric tests are based on western definitions and western cultural practices
Are there Culture-Free Tests ? Attempts have been made to develop culture-free tests of intelligence, but on the whole these attempts have not been successful. This is due to several factors: Conceptions of intelligence vary widely from culture to culture even if the content of a test can be made culture- free, culture itself will still affect the results through directing attitudes towards tests, test-taking, competition, and so on
Examples of RelativelyCulture-Free Psychometric Tests The Leiter International Performance Scale – Revised (Roid & Miller, 1997) covers four domains of functioning: reasoning, visualisation, attention and memory The Ravens Progressive Matrices (Court & Ravens, 1995) covers general cognitive ability Both the above tests are untimed and can be administered using virtually no language
TEST WHY USE TESTS MAIN PARTICIPANTS Test user Test taker Test administrator Test publisher Test author Test reviewer Test sponsor TYPES OF TESTS APPLICATION OF TESTS
PROBLEM Compute the corresponding transformed scores for the given Z scores. ZTPercentileStanine - 0.750 1.500 2.000 0.750 0.555
SOLUTION ZTPercentileStanine - 0.75042.522.664 1.5006593.328.5 2.0007097.729.5 0.75057.577.347 0.55555.55716.61 For 1 st value, For 2 nd value, For 3 rd value,. ˙. T = 10(- 7.50) + 50. ˙. T = 10(1.500) + 50. ˙. T = 10(2) + 50. ˙. T = 42.5. ˙. T = 65. ˙. T = 70 T = 10(Z) + 50 T = 10(Z) + 50 T = 10(Z) + 50 S = 2(Z) + 5.5 S = 2(Z) + 5.5 S = 2(Z) + 5.5. ˙. S = 2(- 0.750) + 5.5. ˙. S = 2(1.5) + 5.5. ˙. S = 2(2) + 5.5. ˙. S = 4. ˙. S = 8.5.. ˙. S = 4 + 5.5. ˙. S = 9.5
Percentile, 0.5 0.2734 0.4332 0.4772 Z = - 0.750 Z = 0 P = 22.66 P = 50 (0.5 – 0.2734) Z = 0 Z = 1.500 P = 50 P = 93.32 Z = 0 Z = 2 P = 50 P = 97.72
For 4 th value, T = 57.5, S = 7 0.2734 0.5 Z = 0 Z = 0.750 P = 77.34 For 5 th value, T = 55.55, S = 6.61 0.21 Z = 0 Z = 0.555 P = 71 0.5
PROBLEM The following are the percentile scores from a Normal Distribution. Find out the Corresponding Z, T and Stanine scores. Sr.NoPercentileZTStanine 116 225 350 475 598
For 3 rd value Z = 0 P = 50 0.5 Z = 0 T = 10( 0 ) + 50 = 50 S = 2( 0 ) + 5.5 = 5.5 For 4 th value 0.5 0.25 Z = 0 Z = 0.675 P = 50 P = 75 Z = 0.675 T = 10(0.675) + 50 = 56.75 S = 10(0.675) + 5.5 = 6.85 (0.75 – 0.50)
For 1 st value For 2 nd value 0. 34 Z = 1 Z = 0 P = 16 P = 50 0.5 T = 10(Z) + 50. ˙. T = 10(- 1) + 50 = 40 S = 2(z) + 5.5. ˙. S = 2(- 1) + 5.5 = 3.5 0.5 0.25 Z = (-)0.675 Z = 0 P = 25 P = 50 Z = 0.67 = 0.2486 Z = 0.68 = 0.2517 0.675 T = 10(- 0.675) + 50 = 43.25 S = 2(- 0.675) + 5.5 = 4.15
For 5 th value 0.5 0.48 Z = 0 Z = 2.06 P = 50 P = 98 T = 10(Z) + 50 = 10(2.06) + 50 = 70.6 S = 2(z) + 5.5 = 2(2.06) + 5.5 = 9.62 Z = 2.06