Unit 1
Psychological tests
Historical antecedents
During the Han dynasty period (206 BC to 220 AD) the use of test batteries became very common. Tests had become an established and accepted instrument for such diverse topics like civil law, military affairs, revenue, agriculture, etc. During the Ming dynasty (1368 to 1644 AD), tests for these various services were used as an accepted norm.
The British government encouraged the East India Company in 1832 to follow the chinese system as a method of selecting employees for overseas duty. The French and the German governments also followed suit after the British government adopted a similar system of testing for civil services in 1855. The US government in 1883.
The beginning of psychological testing relate to the experimental investigation of individual differences that flourished in germany and great britain after 1850. The history of psychological and educational measurement during the period 1850 to 1900, was nourished by three major influences → psychophysics, darwinian biology and clinical practices.
In the second half of the nineteenth century, psychophysics was born and experimental psychologists began to study the relationship between physical stimuli and the experiences and sensation produced by these stimuli. In 1885, the german physician Hubert Von Grashey developed what is called the antecedent of the memory drum as a means of testing patients with brain injury.
Early physiologists were also influencing the development of psychological measurement and were mainly interested in the process of hearing, seeing, speed of conduction etc. As a result, the first laboratory for studying psychological reactions was established in 1879 by Wilhelm Wundt.
Darwin’s theory of evolution also provided a big momentum to the growth of psychological measurement. Sir Francis Galton, half-cousin of Charles Darwin, gathered data on the individual differences of physical and psychological characteristics and wanted to measure the basic individual differences between human beings and singled out ‘human ability’ as a possible dimension of study and laid the foundation stone of the branch of psychology which is today known as psychometrics.
Characteristics
A psychological test is a standardised procedure to measure quantitatively or qualitatively one or more than one aspect of a trait.
a test is an organised succession of stimuli designed to measure quantitatively or to evaluate qualitatively some mental process, trait or characteristic
a psychological test is essentially an objective and standardised measure of sample of behaviour.
a psychological test or educational test is a set of items designed to measure characteristics of human beings that pertain to behaviour.
These definitions reveal some important characteristics of a psychological test →
test is an organised succession of stimuli
the stimuli (known as items) are organised in a certain sequence and based upon some principles of test construction.
a test provides both quantitative and qualitative measurements of a trait
any psychological test or educational test does not assess the totality of a person’s behaviour, rather it is focused on the limited effect of that behaviour.
psychological tests usually provide scores or categories which are interpreted with reference to a standardisation sample.
some psychological tests are norm-referenced tests which means that results from them are interpreted with reference to the average performance of the standardisation sample.
some psychological tests are criterion-referenced which are used to determine where an examinee stands with reference to a tightly defined criterion or educational objective.
objectivity → it must be free from subjective elements so that there is complete interpersonal agreement among experts regarding the meaning of the items and scoring of the test.
reliability → refers to self correlation of the test. it shows the extent to which the results obtained are consistent.
validity → refers to correlation of the test with some outside criterion. it indicates the extent to which the test measures what it intends to measure, when compared with some outside independent criterion which should be regarded as the best index of trait or ability being measured by the test.
norms → refers to the average performance of a representative sample on a given test, help in interpretation of scores. four types → age norms, grade norms, percentile norms and standard score norms.
Classification of test
On the basis of the criterion of administrative conditions
individual tests → these are administered to one person at a time. They are time-consuming and require the services of trained and experiences examiners
eg→ Koh’s block design test
group tests → can be used among more than one person or in a group at a time.
eg → bell adjustment inventory
On the basis of criterion of scoring
objective tests → also known as new-type tests and limited-answer tests
the items in these tests are scored in such a way that no scope for subjective judgement or opinion exist and the scoring remains unambiguous.
subjective tests → also known as essay tests and free-answer tests
the items in these tests are scored in a way which there exists some scope for subjective judgement and opinion, and some elements of vagueness and ambiguity remain in their scoring.
On the basis of the criterion of time limit in producing the response
power tests → they have a generous time limit, usually the items are arranged in increasing order of difficulties.
eg → most intelligence and aptitude tests
speed tests → they have severe time limits but the items are comparatively easy and the difficulties involved are around the same degree.
eg → most clerical tests
On the basis of the criterion of the nature or contents of items
verbal tests → also called paper pencil tests, the items emphasise reading, writing and oral expression.
non-verbal tests → such tests use language in instructions but the items present the problem with the help of figures, pictures and symbols. eg→ Raven’s progressive matrices
performance tests → the emphasise on the examinee’s ability to perform a task ( assemble a puzzle, place pictures in a correct sequence, etc) rather than answer some questions.
usually administered individually to assess the errors committed and time taken to complete the task.
non-language tests → such tests remain independent of the ability to use language, instructions are usually given through gestures or pantomime and examinees respond by pointing at or manipulating objects such as pictures, blocks, puzzles, etc.
On the basis of criterion of purpose or objective
intelligence tests → assess intelligence of the examinees
aptitude tests → assess aptitudes or potentials of the persons
personality tests → assess traits, adjustments, interests, values
neuropsychological tests → assessment of persons with known or suspected brain dysfunction
achievement tests → assess what the persons have acquired as a function of some training or learning
On the basis of the criterion of standardisation
standardised tests → those which have been subjected to the procedure of standardisation. standardised tests are standardised in the sense that they have been administered and scored under standard and uniform testing conditions so that the results obtained from the different samples may legitimately be compared. conditions for standardisation →
a standard manner of giving instructions to maintain uniformity in the evaluation.
uniformity of scoring and index of fairness of correct answer through item analysis
establish reliability and validity of the test and explicitly mention the individuals for whom the test is intended
majority of psychologists favour that standardised tests should have norms.
teacher made tests → those that are constructed by teachers for use largely within their classrooms.
Applications
psychological tests are widely used for many purposes.
in classification → there are different types of classifications each one giving emphasis on a particular purpose in assigning person to categories.
important types of categories are placement, screening, certification and selection
in diagnosis and planning for treatment → diagnosis means determining the nature of a person’s abnormal behaviour and classifying the behaviour pattern with an accepted system.
a proper diagnostic programme provides assignment of label and the choice for treatment.
in self knowledge → administration of psychological test gives feedback to the test takers regarding the level of trait/ability being assessed.
in evaluation of programmes → educational and social programmes such as programmes for betterment of academic achievement or programme for verifying the IQ levels of disadvantaged group.
in theoretical and applied branches of behavioural sciences → psychological tests are very useful in research, psychologists can investigate theoretical matters that have no immediate or obvious practical applications.
in the applied field, such tests can be used by psychologists to test hypothesis and there should not be any debate about testing-based research findings.
Sources of bias in psychological testing
cultural bias
item bias
response bias
acquiescence
social desirability effect
extreme response styles
method bias
construct bias
gender/social role bias
experimenter/observer bias
single bias effect
double bias effect
Ethics of psychological testing
privacy
confidentiality
issues of labelling
informed consent
debriefing