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Lecture 1 - Introduction and History_2007

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									                              Lecture 1 – Introduction and History of Psychometrics … 1


           Lecture 1 –Introduction and History of Psychometrics
Slide 2

-In today’s lecture I will introduce a variety of topics
    -I will define and discuss psychometrics, psychological measurement and
      psychological tests
    -Describe important issues in the application and use of psychological tests
    -Introduce three key concepts in psychometrics, and
    -Describe the history of psychological testing

Slide 3

What is psychometrics?
-The literal meaning of psychometrics is the measurement of the soul
    -Psycho or psyche is Greek for soul and metric means to measure
-Basically psychometrics involves the development, assessment and application of
  methods to assess psychological attributes
-These methods are called psychological measures
-So, psychological measures are methods used to collect a sample of someone’s
  behaviours, thoughts or emotions

Slide 4

-Psychological measures are often called tests although this is strictly not correct
-There are many psychological measures which are not tests
-Examples of non-tests used in psychology are things such as:
    -a single question asking how sad you feel,
    -five questions which ask how you would explain a low grade on a mid-term exam
    -the time it takes for someone to press a button in response to a flashing light
    -the thickness of tiles on a museum floor in front of an new exhibit
-Each of these have been used to measure some psychological attribute and all are not
  tests
-Instead, each of these are a psychological measure

-Measure is the more general term while test is a very specific type of psychological
 measure


-So what are psychological tests?
-According to Anastasi & Urbina, psychological tests are an objective and standardized
  measure of a sample of behaviour
-What this means is that tests collect a small sample of an individual’s behaviour, just
  like a biochemist may collect a sample of blood from someone or a public health officer
  may collect a sample of water from a stream
-The intention is that this sample of behaviours represents the entire domain of the
  person’s behaviour

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-Standardization means that the test is given in the same way and the responses to the test
  are scored in the same way each time the test is administered to test takers
    -So standardization represents both the way the test is administered and how
      responses are transformed into scores on the test

-Tests are often confused with examinations
   -Examinations do not have standard scores or norms, and tend to be used in academic
      situations
   -In contrast, tests are used in academic situations and in non-academic situations

-Psychological tests have become very widespread in Jamaica and in other parts of the
  world
-It is likely that you have already completed tens or even hundreds of psychological or
  educational tests
-Indeed, it is hard to believe that anyone in Jamaica has not completed one or more
  psychological tests
-Psychological tests are used extensively in the education system
     -Students in Jamaica take tests for school readiness, to test their level of academic
        achievement, and to get into high school
     -Employers use a variety of tests to select and promote staff
     -They use intelligence test, tests of managerial ability, personality, and most
        controversially, tests of honesty
-Physicians use psychological tests to screen patients for mental health problems
-Clinical Psychologists use psychological tests to measure intelligence, to diagnose
  mental health problems, to identify neuro-psychological problems, and to track client’s
  progress
-The military also uses psychological tests to assign soldiers to different training
  programmes or for officer training
-Guidance counsellors use tests of interest and aptitude to help high school students to
  select occupations
     -In fact one high school in Kingston is using interest tests to help grade 9 and 10
        students choose occupations
-Researchers use psychological tests and measures to evaluate the effectiveness of social
  programmes and to assign participants to groups in a study

-So, psychological tests are used for a variety of purposes including selection,
  classification, evaluation and research

Slide 5

Important issues in the use of standardized psychological tests

-One of the consequences of the widespread use of psychological tests is their misuse and
  abuse
-Several important issues in the use of psychological tests

   It is important to control the use of tests
-Psychological tests can be misused or misinterpreted by the untrained

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-When used by untrained people, the improper use of psychological tests can have many
  harmful consequences both for the test taker and for the test itself
-When administered by an untrained person, scores on psychological tests may be
  misleading or completely incorrect
-For the test itself, it is important to limit the availability of the test to protect general
  knowledge of the content of the test
    -General knowledge a test’s content may artificially increase or alter the performance
      of test takers on the test
    -This means that the test will no longer be a representative sample of a person’s
      behaviour or knowledge

Slide 6

     The importance of standardized administration of tests
-It is important that psychological tests be administered in the same way by all test
  adminstrators so that the test is a valid sample of people’s behaviours
-Having a valid sample of someone’s behaviour means that the results of the test can be
  generalized to situations outside of the original test taking situation
-Giving the test in the same way by all examiners is part of the standardization of the test
-Altering how the test is given will alter how accurately the test will sample the test
  taker’s behaviours and how well the test will be able to predict behaviour in the real
  world

Slide 7

    Factors which can impact performance on standardized tests
-Several factors can impact test takers’ scores on psychological tests
-First, the familiarity and preparation of the test administrator with the test
    -Increased familiarity and greater preparation for giving the test results in less
      variability in test takers’ scores
-The demeanour and behaviour of the test administer can alter scores on the test
    -A sense of rapport and ease between the test administrator and the test taker will
      improve the test taker’s scores
-Variables such as the test administrator’s age, gender, ethnicity and social class can also
  affect test takers’ scores
    -The more similar the test administrator is the test taker the better the test scores will
      represent the test taker’s true capabilities
-The conditions under which the test is given can affect a test taker’s scores
    -The more similar the testing conditions are for the test taker to those experienced by
      the sample of people in the standardization sample the greater the likelihood the
      scores can be generalized to situations outside of the test
-The anxiety of the test taker can impact test scores
    -The more anxious the test taker the less accurate their scores on the test

Slide 8

-Coaching on the test can impact test performance, especially for disadvantaged
  populations

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    -Coaching is teaching test takers special strategies that can be used to more quickly
      respond to items on a test
    -For example, teaching students short cuts to solving math problems on the test
-Coaching does not lead to increases in the test taker’s abilities outside of the test, only to
  increases in scores on the test
-Education on the other hand, will increase both test takers’ scores on the test and their
  future ability to do tasks like the ones on the test
-Finally, the number of times a test taker has taken standardized tests or his/her past
  experience in taking a specific test can lead to artificial increases in test taker’s scores
-The more often someone has taken a specific test or the more standardized tests that
  someone has taken, the higher will be their scores on a test

Slide 9

Key concepts in psychometrics
-To truly understand pyschometrics there are three core concepts in that you must master:
   1) Measurement
   2) Reliability, and
   3) Validity

-Measurement is the process of assigning numbers to our observations of real world
 events

Slide 10

-Basically, measurement is the process of creating a language to represent what we
  observe
-This language is simply a series of numbers which take the place of the actual events we
  are observing
-In fact, the first real use of a number system was in ancient Egypt
    -The Egyptians needed a method to identify what were in sealed clay jars
    -To help them they simply drew pictures on the lids of the jars to represent what was
      in the jar
    -If a jar contained three bunches of wheat the Egyptians drew three bunches on the lid
      of the jar
    -You can see the remnants of this system in Roman numerals
-The test of any measure is the extent to which the numbers assigned to our observations
  actually match the behaviour of the thing or process we are observing

Slide 11

-Reliability is simply how stable or repeatable the numbers collected using the
  psychological measure are
-We say that something is reliable if it performs in the same way each time
-For example, a car is reliable if it starts each time we turn the key to start it
-So, a psychological measure is reliable if it generates the same numbers for a person
  each time the person is observed using the psychological measure


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Slide 12

-Validity is the accuracy of the numbers collected using the psychological measure
-We say that a psychological measure is valid if the data it collects correctly represents
  the psychological process we’re observing
-For example, a measure of depression would be valid if the scores on the measure
  accurately corresponded to people’s depressed behaviour such as feeling sad, sleeping
  in late, feeling hopeless, etc.

Slide 13

History of psychometrics
-Practice of using tests has been around for a long time
-Testing evolved because of a demand from three different areas: the civil service, the
  education system, and the study of individual differences

Slide 14

    In the civil service
-The first recorded use of a civil service test occurred about 3,000 years ago in China
  when the emperor decided to test the competency of all of his officials or Mandarins
-These tests covered knowledge of music, horsemanship, civil law, writing, Confucian
  principles, and public and private ceremonies
    -Eventually the tests were used to select and promote people in the Chinese civil
      service
    -To advance through the hierarchy employees had to write a test
-The Chinese stopped using these tests around 1905
-Coincidentally, governments in the West (the US and the UK) began to implement civil
  service exams about this same point in time
-Purpose of the tests was to eliminate favouritism and cronyism in hiring government
  employees
-The idea was that a test would remove political influence from who was hired and would
  create a professional public service

Slide 15

    In the education system
-Tests have had a long history of use in educational settings
-The ancient Greeks used tests of the mastery of students’ learning as well as their
  physical skills
-These tests were integrated into the teaching process called the Socratic method
-Tradition of oral exams continued for many years
-Students in European schools were given oral exams to test their knowledge of course
  material until the 12th century




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Slide 16

-With the rise of paper and the printing press, examinations became written rather than
  oral tests
-Jesuits in the 16th century began using written tests to evaluate and place their students
  into different classes
-Later, during the early 1900’s, standardized tests of students’ learning were created
-These tests are called tests of academic achievement
-The first versions of these tests were modelled after tests of intelligence and were
  initially developed by psychologists interested in studying intelligence
-The practice of standardized testing of academic achievement has become widespread
-Today virtually no student in Jamaica has not taken a standardized test of academic
  achievement

Slide 17

    In research on individual differences
-The major thrust for the development of psychological tests was interest in individual
  differences
    -In the early days of psychology, psychologists were interested in finding general
      laws governing human behaviour
    -As such, the study of individual differences were not of interest
    -In fact, individual differences were though of as merely errors which should be
      eliminated or ignored
    -Today, the field of psychology is principally focused on individual differences

-The English Biologist, Sir Francis Galton, was principally responsible for starting an
  interest in individual differences and testing
-In fact, you could call Galton the great-grandfather of psychological testing and
  assessment
-Galton was searching for the roots of heredity or what makes children resemble their
  parents and siblings resemble each other
-To do this he realized that he needed to study individual differences in physical
  characteristics
-He set-up a laboratory at the International Exposition of 1884 and charged people for the
  right to take measures of their physical and sensory features

Slide 18

-Galton came up with the idea that tests of sensory discrimination could be used to judge
  intelligence
-This was based on his observation that the severely intellectually challenged had greater
  difficulty than non-intellectually challenged people in distinguishing heat, cold, and
  pain
-From this he derived the belief that simple measures of sensory discrimination could be
  used to measure intelligence
-Galton also pioneered the development of questionnaire and rating scale methods


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-He was also responsible for taking existing mathematical methods and adapting them for
  use in studying individual differences

-James Cattell was one of the first psychologists to study individual differences, thereby
  shaking up the psychological Dons of the day
-Did his Ph.D. on individual differences in reaction time
-Cattell met Galton while at Cambridge University and became even more interested in
  the study of individual differences
-His contact with Galton furthered his belief that tests of sensory discrimination could be
  used to assess intelligence
-He developed a series of tests to test the intelligence of incoming university students
-These tests measured muscular strength, speed of movement, sensitivity to pain,
  keenness of vision and hearing, weight discrimination, reaction time, and memory
-Based his selection of tests on the fact that methods of measuring these functions were
  available and could generate precise data
    -In essence, he invented the college entrance exam

Slide 19

-In a paper describing his tests of university students Cattell coined the term “mental test”
  thereby becoming the first person to use the term test in a published paper in
  psychology

-The French government, in move to better educate the intellectually challenged, wanted
  a way to identify children with these difficulties
-They asked the French Psychologist, Alfred Binet, to develop a measure which could be
  used to identify these children
-In collaboration with Simon he developed the first true test of intelligence, the Binet-
  Simon Scale
-Binet and Simon’s scale had 30 problems which were arranged in order of increasing
  difficulty
-The difficulty level was empirically determined by asking 50 normal children 3 to 11
  years of age to do the tests, and then a small sample of intellectually challenged
  children and adults
-A version of this first intelligence test, the Stanford-Binet, is still in use today

Slide 20

-All of these tests of intelligence and sensory discrimination were individually
  administered tests, meaning that they could be only administered to one person at a
  time
-This was impractical if you needed to assess a large number of people
-The first world war brought about the need to test large numbers of people quickly thus
  spurring the development of group tests of intelligence and revolutionizing the process
  of psychological testing
-Unlike the English who selected officers on the basis of their family background or
  social class, the American military needed a fairer method to select possible officers
-They also needed a fast way of screening more than a million recruits

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-Because of migration, many people in the U.S. in the early 1900’s could not speak
  English or had limited knowledge of English
-The American Psychological Association wanted to aid the war effort so they
  established a committee to develop a method of rapidly assessing the vast number of
  recruits
-Under the direction of Robert Yerkes, two group administered tests of intelligence were
  created from existing measures of intelligence; the army alpha and the army beta
    -Refined versions of these two tests are still in use today
-These tests inspired many other group administered tests of intelligence and other
  attributes to be developed and applied on a wide scale basis
-Thus, the move to large scale testing emerged

-Tests of aptitude emerged from the realization that the existing tests of intelligence
  assessed a very narrow range of abilities
-These tests were used in vocational guidance and to help the military and businesses to
  select people for specific types of jobs

Slide 21

-Spearman, Kelly, and Thurstone, as well as Raymond Cattell, developed a method of
  studying the inter-relationship of scores on various tasks on intelligence tests
-Out of this effort emerged Factor Analysis which was used to further the development of
  tests and led to many new forms of personality, interest, aptitude and intelligence tests

-Thorndike around the turn of the last century developed the first tests of academic
  achievement
-Done in response to the need for more objective measures of academic achievement than
  teacher’s subjective judgments
-Thorndike used the methods developed to create intelligence tests to create tests of
  academic achievement
-Thus, academic achievement tests came to resemble in many respects standardized tests
  of intelligence
-This led to the widespread use of achievement tests in school systems and for selection
  of applicants for university
-So, you can all blame Thorndike for all those standardized academic achievement tests
  you’ve had to take in Jamaica including the Common Entrance Exam and the Grade Six
  Achievement Test (GSAT)

-Tests of personality emerged as a distinct field from intelligence and academic
  achievement
-Started with the belief that the free association technique could be used to measure and
  distinguish between different forms of mental illness
-The first world war saw the use of free association tests to identify recruits who had
  psychological problems which make them unfit for military service

Slide 23

-The 1920’s and 1930’s saw the development of performance based personality tests

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-In these tests a person is asked to perform a task whose true purpose is masked
-During the second world war the Office of Strategic Services used these tests to select
  people who make good spies

-Projective personality tests also emerged during the first half of the 1900’s
-These tests provided people with an ambiguous stimulus, such as a picture of two people
  in a home
-Respondents are asked to describe what they saw in the picture or to tell a story about
  what is happening
-The idea is that the respondent will project their characteristic modes of response or
  behaviour into the task




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