DAV PG College Psychology Composed by Dr Aparna

DAV PG College Psychology Composed by Dr. Aparna Pathak Created with the help of below mentioned sites APA Standards for Educational and Psychological Testing Joint Committee on Standards for Educational Evaluation Psychometric Society and Psychometrika homepage London Psychometric Laboratory Rasch analysis in psychometrics Also taken help from book which is prescribed for PG. 2 nd semester : Statistics for Social Sciences

Psychometrics is the field of study concerned with theory and technique of educational and psychological measurement, which includs the measurement of knowledge, abilities, attitudes, and Personality traits. The field is primarily concerned with the study of measurement instruments such as Questionnaires and tests. It involves two major research tasks, namely: (i) the construction of instruments and procedures for measurement; and (ii) the development and refinement of theoretical approaches to measurement.

Application , Scope Psychometric theory has been applied in the measurement of personality, attitudes and beliefs, academic achievement, and in health-related fields. Measurement of these unobservable phenomena is difficult, and much of the research and accumulated art in this discipline has been developed in an attempt to properly define and quantify such phenomena. Critics, including practitioners in the physical science and social activists, have argued that such definition and quantification is impossibly difficult, and that such measurements are often misused. As with psychometric personality tests used in employment procedures.

Psychometrics is also applied widely in educational assessment to measure abilities in domains such as reading, writing, and mathematics. The main approaches in applying tests in these domains have been Classical Test theory. and the more modern Item Response Theory and Rasch measurement models. These modern approaches permit joint scaling of persons and assessment items, which provides a basis for mapping of developmental continua by allowing descriptions of the skills displayed at various points along a continuum for example using a visual analogue scale. Such approaches provide powerful information regarding the nature of developmental growth within various domains.

Levels of measurement The major focus in psychometrics have been on personality training. There have been a range of theoretical approaches to conceptualising and measuring personality. Some of the better known instruments include the Minnesota Multiphasic Personality Inventory. The key traditional concepts in classical test theory are Reliability and validity. Both reliability and validity may be assessed conceptually and mathematically. Internal consistency may be assessed by correlating performance on two halves of a test (split-half reliability); the value of the Pearson Product- moment correlataion coefficient. is adjusted with the Spearman - Brown Prediction Formula to correspond to the correlation between two full-length tests. Other approaches include the intraclass correlation (the ratio of variance of measurements of a given target to the variance of all targets). A commonly used measure is Chronbach’s alpha, which is equivalent to the mean of all possible split -half coefficients. Stability over repeated measures is assessed with the Pearson coefficient, as is the equivalence of different versions of the same measure (different forms of an intelligence test, for example).

Parameter • A psychometric function is fitted to the four points (each with several trials) to estimate threshold and slope parameters of the psychometric function. Adaptive methods, such as the up-down methods [H. Levitt, J. Acoust. Soc. Am. 49, 467 -477 (1971)], can be used to provide good initial estimates of the threshold and spread parameters of a psychometric function described by a logistic function.

• In ongoing studies of age-related changes in auditory masking and discrimination, this new four-point sampling method has been applied to determine psychometric functions for absolute thresholds as a function of duration, thresholds in simultaneous and forward masking, frequency discrimination, and intensity discrimination in both young and aged human subjects. Results indicate that a reduction in data collection time of about 50% with no increase in variance can be achieved. This increase in efficiency applies to simple detection tasks by normal hearing subjects as well as to complex discrimination tasks by older subjects with hearing loss.

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