1. Foundations of Psychological Assessment
Dr Dinesh Ramoo

2. Introduction to the Course
This course will consist of tutorials, practical activities, assignments and examinations.
There will be periodic practical activities which you will need to attend and collect the activity sheets into a booklet. You will need to submit it to the tutor at the specified deadlines.
There is one assignment for which you will need to collect experimental data and submit an analysis of the results.
There will be one mid-term examination and one final examination.

3. General Housekeeping
Please note that you will only get marks for practical activities if you attend the sessions in class.
It is your responsibility to attend the classes and to keep track of your attendance. The lecturer will not inform you of your attendance.
It is your responsibility to submit the correct files for assignments. If the files are corrupted they will not be marked.
Plagiarism (copying directly from other sources) will not be tolerated.

4. Introduction

5. Introduction
Psychometrics is a field of study concerned with the theory and technique of psychological measurement.
One part of the field is concerned with the objective measurement of skills and knowledge, abilities, attitudes, personality traits, and educational achievement.
For example, some psychometric researchers have, thus far, concerned themselves with the construction and validation of assessment instruments such as questionnaires, tests, raters' judgments, and personality tests.

6. Introduction
Another part of the field is concerned with statistical research bearing on measurement theory (e.g., item response theory; intra-class correlation).
As a result of these focuses, psychometric research involves two major tasks:
the construction of instruments; and
the development of procedures for measurement.

7. What is Measurement?
Measurement is the assignment of numbers to properties or attributes of people, objects or events using a set of rules, according to Stevens (1946, 1968). From this definition several characteristics of measurement may be derived (Aguinis, Henle and Ostroff, 2001):
It focuses on attributes of people, objects or events not on actual people, objects or events.
It uses a set of rules to quantify these. They must be standardized, clear, understandable and easy to apply.
It consists of scaling and classification. Scaling deals with assignment of numbers so as to quantify them, i.e. to determine how much of an attribute is present. Classification refers to defining whether people, objects or events fall into the same or different categories.

8. Process of Measurement
Its purpose should be determined, for example, in prediction, classification or decision-making.
The attribute should be identified and defined. A definition needs to be agreed before it is measured or different rules may be applied, resulting in varying numbers being assigned. The purpose of measurement should guide this definition.
A set of rules, based on the definition, should be determined to quantify the attribute.
Lastly, the rules are applied to translate the attribute into numerical terms.

9. Benefits of Measurement
The key benefit is objectivity, which minimises subjective judgement and allows theories to be tested (Aguinis, 1993).
Measurement results in quantification. This enables more detail to be gathered than through personal judgements.
More subtle effects can be observed and statistical analysis used to make precise statements about patterns of attributes and relationships (Pedhazur and Pedhazur Schmelkin, 1991).
Better communication is possible because standardized measures lead to a common language and understanding.

10. History of Psychometrics
The Measure of Man

11. Early speculations about individual differences
The Greek philosophers Plato and Aristotle discussed individual differences in their works.
However, their method was qualitative and did not focus on actual measurement of cognitive abilities.
Interest in individual differences declined in the Middle Ages due to an idea that conformity was the preferable state for human beings.

12. Early Psychological Tests
Although the widespread use of psychological testing is largely a phenomenon of the twentieth century, historians note that rudimentary forms of testing date back to at least 2200 B.C. when the Chinese emperor had his officials examined every third year to determine their fitness for office (Bowman, 1989; Chaffee, 1985; DuBois, 1970; Franke, 1963; Lai, 1970; Teng, 1942–43).
Such testing was modified and refined over the centuries until written exams were introduced in the Han dynasty (202 B.C.–A.D. 200).
Five topics were tested: civil law, military affairs, agriculture, revenue, and geography.
The Chinese examination system took its final form about 1370 when proficiency in the Confucian classics was emphasized.

13. The Chinese Examination System
In the preliminary examination, candidates were required to spend a day and a night in a small isolated booth, composing essays on assigned topics and writing a poem.
The 1 to 7 percent who passed moved up to the district examinations, which required three separate sessions of three days and three nights.
The district examinations were obviously grueling and rigorous, but this was not the final level.
The 1 to 10 percent who passed were allowed the privilege of going to Peking for the final round of examinations.
Perhaps 3 percent of this final group passed and became mandarins, eligible for public office.

14. Differences between Ancient and Modern Tests
Although the Chinese developed the external trappings of a comprehensive civil service examination program, the similarities between their traditions and current testing practices are, in the main, superficial.
Not only were their testing practices unnecessarily grueling, the Chinese also failed to validate their selection procedures.
Nonetheless, it does appear that the examination program incorporated relevant selection criteria.
For example, in the written exams beauty of penmanship was weighted very heavily. Given the highly stylistic features of Chinese written forms, good penmanship was no doubt essential for clear, exact communication. Thus, penmanship was probably a relevant predictor of suitability for civil service employment.
In response to widespread discontent, the examination system was abolished by royal decree in 1906 (Franke, 1963).

15. Transition into Modern Psychometrics
By the seventeenth century post-Renaissance philosophers began to look at ideas, events and phenomena in more scientific ways, leading to a new way of thinking called ‘empiricism’. This said that all factual or true knowledge comes from experience and was developed by John Locke into an organized school of thought.
When Charles Darwin provided an account of the mechanisms of evolution between 1858 and 1877, he influenced early psychology. His principal thesis was that members of a species exhibit variability of characteristics and this variability results in some being better suited than others to any particular set of environmental conditions.
His term ‘characteristic’ meant anything which could be attributed to an individual organism, for example agility or height. Those best adapted would reproduce more prolifically, possibly being the only ones to survive to maturity and reproduce.
The significance of individual differences between those belonging to the same species was, therefore, a key factor which influenced early psychologists and statisticians, many of whom contributed to the development of a new science of mental measurement.
Experimental psychologists such as Gustav Fechner, Wilhelm Wundt and Hermann Ebbinghaus, discovered that psychological phenomena could be described in rational and quantitative ways.

16. Francis Galton (1822 – 1911)
Especially important was the Englishman Francis Galton (1822–1911), whose career was similar to that of his cousin Darwin.
You are in good company if you have felt close to a breakdown before exams because Galton studied maths at Trinity College, Cambridge, and suffered a breakdown before his finals so he didn’t get a very good honours degree.
Galton adopted the new scientific ideas which he thought could be proven only by careful enquiry and used his wealth to pursue this. Among many other interests, he became obsessed with making all kinds of measurements of people in his research laboratory.
More than 17,000 people paid for the privilege of providing measurements, such as height, weight, strength, rate of movement and reaction times. Galton was a prolific writer and a zealous scientist.
Galton was the first to emphasize the importance of individual differences, created the first tests of mental ability and was the first to use questionnaires.
He discovered a number of statistical procedures to analyse data, many still in use today, for example he found that a wide range of measures of human physiology and abilities produce what is still referred to as a ‘normal curve’, sometimes as the ‘bell curve’ or ‘normal distribution’. He said this curve could be meaningfully summarized by its mean and standard deviation, and suggested the use of these to describe measures of human attributes.
Galton also invented the scatter-plot to illustrate data. His application of exact quantitative methods resulted in the discovery of a numerical factor which he called correlation, specifying the degree of relationship between individuals or any two attributes. He was one of the first to realize the importance of posted questionnaires, which he accompanied with prizes!

17. Alfred Binet (1857 – 1911)
The Frenchman Alfred Binet (1857–1911) had a rather different background, being the child of a single mother who took him to Paris at the age of 15.
He qualified in law but then switched to medicine, although his interest in psychology was more important.
Working at the Sorbonne in 1891, he became assistant director of the laboratory of physiological psychology and in 1905 opened a Paris laboratory for child study and experimental teaching.
Influenced by Galton’s work, he was appointed to a ministerial commission to study the plight of retarded school children to ensure they would have an adequate education. A mechanism was needed to identify pupils in need of alternative education.
So Binet set out to identify the differences that separate the abnormal child from the normal and to measure them.

18. Stanford–Binet Intelligence Test
He constructed a series of tests, including short, varied problems about daily life, as well as tests of cognitive processes such as memory.
They were made up of a series of tasks thought to be representative of a typical child’s abilities at different ages.
Binet ranked the tests in accordance with age levels corresponding to performances by the average child.
In doing so he distinguished between the mental age attained on the scale and the chronological age of a child. The outcomes, developed with his assistant Theodore Simon, were received throughout the world with wide acclaim.
Binet and Simon published their last revision in 1911 (Binet and Simon, 1911; Binet, 1916; Binet and Simon, 1916).
In the United States Lewis Terman (1877–1956) standardized the Binet–Simon scale using sampling methods, resulting in what has since been called the Stanford–Binet Intelligence Test (Terman, 1916, 1917).

19. Important Figures in Psychometrics
Karl Pearson (1857–1936)
Wrote papers which contributed to the development of regression analysis and the correlation coefficient (think of the Pearson Product–Moment Correlation Coefficient), and discovered the chi-square test of statistical significance.
Louis Thurstone (1887–1955)
Designed techniques for measurement scales, for the assessment of attitudes and developed test theory (Thurstone, 1919, 1953). His major contribution was in the creation of new methods of factor analysis to identify the nature and number of potential constructs within a set of observed variables.
Georg Rasch (1901–1980)
Best known for his contribution to psychometrics through the development of a group of statistical models known as Rasch models (Rasch, 1980). In these the selection of questions to give a precise estimate of ability is based upon a rigorous model.

20. Important Figures in Psychometrics
Raymond Cattell (1905–1998)
A major influence on the theoretical development of personality as he sought to apply empirical techniques to understand its basic structure (Cattell, 1965). He extended existing methods of factor analysis and explored new approaches to assessment, and has been unrivalled in the creation of a unified theory of individual differences, combining research in intelligence with that of personality.
Anne Anastasi (1908–2001)
Undertook major studies of test construction, test misuse, misinterpretation and cultural bias, and was the author of the influential book Psychological Testing (1988),which has been the core text in this field since its first edition in 1954.
Paul Kline (1937–1999)
He did much to explain what has become an increasingly complex field and provided evaluations of the most widely-used tests. In The New Psychometrics: Science, Psychology and Measurement (1998), he argued that truly scientific forms of measurement could be developed to provide a new psychometrics which would transform psychology from a social to a pure science.

21. Development of Manuals
All of this has resulted in a continuing commitment to the development of assessment classifications, extending them to include ‘milder’ and ‘borderline’ cases and many new conditions such as Post-Traumatic Stress Disorder (PTSD) and Attention-Deficit Hyperactivity Disorder (ADHD).
The handbook for this is known as the Diagnostic and Statistical Manual of Mental Disorders (DSM), of the American Psychiatric Association, first published in 1952, which was based on the ‘mental disorders’ sections of the International Classification of Diseases (ICD) published by the World Health Organization.
The ICD, the latest version of which is the ICD-10, classifies both mental and physical disorders, and is more widely used in Europe (World Health Organization, 2004).
There is now a large degree of overlap between the two systems.

22. Psychological Testing
Measuring Behaviour

23. Taxonomy of Psychological Assessments
Measurement
Correct/incorrect item responses
Tests
Scales
Not using correct/incorrect item responses
Questionnaire
Inventories
Non-measurement
Non-metric measures
Interviews
Observations
Checklists

24. Basic Elements of Psychological Tests
Defining Element
Explanation
Rationale
Psychological tests are systematic
procedures
They are characterised by planning, uniformity, and thoroughness
Test must be demonstrably objective and fair to be of use
Psychological tests are samples of behaviour
They are small subsets of a much larger whole
Sampling must be efficient due to time limitations
The behaviours sampled by tests are relevant to cognitive or affective functioning or both
The samples are selected for their empirical or practical psychological significance
Tests are tools
Test results are evaluated and scored
Some numerical or category system is applied to the results
There should be no ambiguity regarding the test results
Test result standards should be based on empirical data
There should be a way of applying a common criterion to test results
The standards used to evaluate test results lend the only meaning those results have

25. Principles of Psychological Testing
Standardization - All procedures and steps must be conducted with consistency and under the same environment to achieve the same testing performance from those being tested.
Objectivity - Scoring such that subjective judgments and biases are minimized, with results for each test taker obtained in the same way.
Test Norms - The average test score within a large group of people where the performance of one individual can be compared to the results of others by establishing a point of comparison or frame of reference.
Reliability - Obtaining the same result after multiple testing.
Validity - The type of test being administered must measure what it is intended to measure.

26. Psychological Testing vs. Psychological Assessment
Psychological tests may be key components in psychological assessment, but the two differ fundamentally in important ways.
Even though there is little question about the general superiority of assessment over testing with regard to comprehensiveness and utility, the greater complexity of the assessment process makes its results far more difficult to evaluate than those of testing.
Nevertheless, in recent years, evidence of the efficacy of assessment, at least in the realm of health care delivery, has begun to be assembled (Eisman et al., 2000; Kubiszyn et al., 2000; Meyer et al., 2001).

27. Psychological Testing and Assessment
Basis
Psychological Testing
Psychological Assessment
Degree of complexity
Simpler; involves one uniform procedure, frequently uni-dimensional
More complex; each assessment involves various procedures and dimensions.
Duration
Shorter; lasting from a few minutes to a few hours
Longer; lasting from a few hours to a few days
Sources of Data
One person, the test taker
Often collateral sources, such as relatives or teachers, are used in addition to the subject of the assessment.

28. Psychological Testing and Assessment
Basis
Psychological Testing
Psychological Assessment
Focus
How one person or group compares with others (nomothetic)
The uniqueness of a given individual, group, or situation (idiographic)
Qualifications for use
Knowledge of tests and testing procedures
Knowledge of testing and other for assessment methods as well as of the area assessed (e.g., psychiatric disorders, job requirements).
Procedural basis
Objectivity required; quantification is critical
Subjectivity, in the form of clinical judgment, required; quantification
rarely possible.

29. Psychological Testing and Assessment
Basis
Psychological Testing
Psychological Assessment
Cost
Inexpensive, especially when testing is done in groups
Very expensive; requires intensive use of highly qualified professionals.
Purpose
Obtaining data for use in making decision
Arriving at a decision concerning the referral question or problem.
Degree of Structure
Highly structured
Entails both structured and unstructured aspects.
Evaluation of results
Relatively simple investigation of reliability and validity based on group results.
Very difficult due to variability of methods, assessors, nature of presenting questions, etc.

30. Questions?