Objective Personality Assessment

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Objective Personality Assessment

• Tony Donofrio, Ph.D., P.C.

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Defining Personality

• How would you define personality
• Definitions of Personality
• A unique composite of inborn and acquired mental
  abilities, temperaments, attitudes, and other
  individual differences in thoughts, feelings, and
  actions. This collection of cognitive and
  affective characteristics, as it exists in a
  particular person, is associated with a fairly
  consistent, predictable pattern of behavior
  (Aiken, 1999).
• The dynamic organization within the individual
  of those psychophysical systems that determine
  his characteristic behavior and thought
  (Allport, 1937, p. 48, as cited in Feist, 1994).
• An individuals unique constellation of
  consistent behavioral traits (Weiten, 1999)

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Defining Personality

• Definitions of Personality
• That which permits a prediction of what a person
  will do in a given situation (Cattell, as cited
  in Feist, 1994)
• The intrinsic organization of an individuals
  mental world that is stable over time and
  consistent over situations (Piedmont, 1998, p.
  2)

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Brief History of Personality Assessment

• Biblical allusions to personality dimensions
• Numbers 123 Now Moses was a very humble man,
  more humble than anyone else on the face of the
  earth.
• 1Chronicles 49 Jabez was more honorable than
  his brothers. His mother had named him Jabez,
  saying, "I gave birth to him in pain."
• 2 Chronicles 2934 The priests, however, were too
  few to skin all the burnt offerings so their
  kinsmen the Levites helped them until the task
  was finished and until other priests had been
  consecrated, for the Levites had been more
  conscientious in consecrating themselves than the
  priests had been.
• 12 But you have behaved more wickedly than your
  fathers. See how each of you is following the
  stubbornness of his evil heart instead of obeying
  me.

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Brief History of Personality Assessment

• Biblical allusions to personality dimensions
• Luke 168 "The master commended the dishonest
  manager because he had acted shrewdly. For the
  people of this world are more shrewd in dealing
  with their own kind than are the people of the
  light.
• Acts 1711 Now the Bereans were of more noble
  character than the Thessalonians, for they
  received the message with great eagerness and
  examined the Scriptures every day to see if what
  Paul said was true.
• 1 Corinthians 1533 Do not be misled "Bad
  company corrupts good character." 34Come back to
  your senses as you ought, and stop sinning for
  there are some who are ignorant of God--I say
  this to your shame.

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• Judges 72-7 2The LORD said to Gideon, You have
  too many men for me to deliver Midian into their
  hands. In order that Israel may not boast
  against me that her own strength has saved her,
  3announce to the people Anyone who trembles with
  fear may turn back and leave Mount Gilead So
  twenty-two thousand men left, while ten thousand
  remained.
• 4But the LORD said to Gideon, There are still
  too many men. Take them down to the water, and I
  will sift them for you there. If I say This one
  shall go with you, he shall go but if I say
  This one shall not go with you, he shall not
  go.
• 5So Gideon took the men down to the water.
  There the LORD told him Separate those who lap
  the water with their tongues like a dog from
  those who kneel down to drink. 6Three hundred
  men lapped with their hands to their mouths. All
  the rest got down on their knees to drink.
• 7The LORD said to Gideon With the three
  hundred men that lapped I will save you and give
  the Midianites into your hands. Let all the
  other men go, each to his own place.

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• What are the important dimensions to consider in
  studying (understanding) personality
• Continuums

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Brief History of Personality Assessment

• Hippocrates (460-377 B.C.)
• Described the four humors
• (1) Phlegm, (2) Yellow bile, (3) Black bile, and
  (4) Blood
• Galen (c. 200 A.D.)
• Subscribed to the humoral theory introduced by
  Hippocrates
• Proposed that ones temperament was associated
  with an overabundance of the humors
• Blood Sanguine personality (forceful, direct,
  and courageous)
• Black bile Melancholic personality (moody,
  brooding, and withdrawing)
• Yellow bile Choleric personality (irritable,
  bitter, resentful)
• Phlegm Phlegmatic personality ( weak, fragile,
  and indecisive)

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Brief History of Personality Assessment

• Gall Spurzheim
• Propagated the pseudoscience of phrenology (study
  of the mind)
• Contended that proturbances and indentations on
  the human skull reflected the size of the
  underlying brain areas and hence an abundance or
  deficit of the faculty thought to be associated
  with that region.
• Derived from Galls
• Childhood experiences and
• subsequent work in anatomy

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Theories of Personality

• Type Theories
• Assign individuals to categories or static
  classifications
• Phsiognomy attempted to identify personality
  characteristics based upon various body features,
  particularly of the face
• Sheldons Somatotypes
• Endomorphy (viscerotonia) connected with jolly,
  sociable, comfort-seeking characteristics these
  individuals enjoy eating
• Mesomorphy (somatotonia) associated with
  qualities of assertiveness, noisiness,
  callousness, dominance, a youthful orientation,
  and love of physical exercise
• Ectomorphy (cerebrotonia) affiliated with
  emotional restraint, introspection,
  fast-reacting, hypersensitivity to pain, and
  sleep problems

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• Endomorphic Body Type
• soft body
• underdeveloped muscles
• round shaped
• over-developed digestive system
• Associated personality traits
• love of food
• tolerant
• evenness of emotions
• love of comfort
• sociable
• good humored
• relaxed
• need for affection

• Mesomorphic Body Type
• hard, muscular body
• overly mature appearance
• rectangular shaped
• thick skin
• upright posture
• Associated personality traits
• adventurous
• desire for power and dominance
• courageous
• indifference to what others think or want
• assertive, bold
• zest for physical activity
• competitive
• love of risk and chance

• Ectomorphic Body Type
• thin., flat chest
• delicate build
• young appearance
• tall
• lightly muscled
• stoop-shouldered
• large brain
• Associated personality traits
• self-conscious
• preference for privacy
• Introverted, inhibited
• socially anxious
• artistic
• mentally intense
• emotionally restrained

http//www.kheper.net/topics/typology/somatotypes.
html
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Theories of Personality

• Trait Theories
• Gordon Allport
• Trait a predisposition to respond in a
  particular way to persons, things, or situations
• Allport Odbert (1936) were forerunners of the
  lexical approach
• Allport assumes that traits vary in terms of
  their pervasiveness and generality
• Generality
• Common traits shared across a population
  permits interindividual comparisons (e.g., kind,
  sociable)
• Personal dispositions (5 or 10 to hundreds)
  unique, individual traits, that stylistically
  guide behavior by rendering diverse stimuli
  functionally equivalent (e.g. quixotic,
  narcissistic, etc.)
• All PDs are motivational (dynamic)
• Pervasiveness
• Cardinal trait - a dominant trait that
  characterizes nearly all of a persons behavior
• Central traits (5-10) - prominent general
  dispositions found in anyone
• Secondary traits - dispositions that surface in
  some situations but not in others
• Proprium

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Theories of Personality
Continuum of Personal Dispositions
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Theories of Personality

• Trait Theories
• Raymond Cattell
• Adopted an inductive approach to the study of
  personality traits
• Distinguished between source traits and surface
  traits
• Surface traits situationally exhibited ways of
  responding
• Source traits the underlying or deeper-level
  trait that serves as a better predictor of
  behavior and is more consistent across situations
  (these traits account for the intercorrelations
  among surface traits).
• Utilized the work of Allport and Odbert (1936) to
  conduct factor analysis on personality traits
• Factor analysis predominately a data-reduction
  technique used to identify latent (underlying)
  constructs from a larger array of variables.
• Example unselfish, helpful, altruistic, gentle,
  tender-minded
• Example talkative, confident, gregarious,
  optimistic, energetic, assertive
• Identified 35 Personality Traits to describe
  individuals
• 23 considered normal
• 12 considered abnormal
• The level of each traits possessed by a person
  differs

Q, L, T data
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• Factor Analysis

Factor 1 Factor
2 Gregariousness 0.514
0.103 Assertiveness 0.622
0.087 Energy 0.583
0.216 Organization 0.143
0.397 Aspirations 0.092 0.499
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• Jesus Factor Analysis ?!?

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Theories of Personality

• Trait Theories
• Raymond Cattell
• Third traits dimension
• Temperament traits concerned with how a person
  behaves
• Motivation (dynamic) traits concerned with why
  an individual behaves in a certain manner
• Ability traits refer to how far or how fast
  someone can respond
• Pathology defined as exaggerated normal traits of
  presence of abnormal traits
• Hans Eysenck
• Organized personality along a four-tiered
  hierarchy
• Specific acts or cognitions may or may not be
  characteristic of a person (e.g., completing an
  assignment)
• Habitual acts or cognitions response that recur
  under similar circumstances with reasonable
  consistency (consistently completing assignments
  in various classes)
• Traits semi-permanent personality dispositions
  represented by several related habitual responses
  (e.g., completing assignments and finishing
  chores persistence)
• Types several interrelated traits (e.g.,
  extraversion)

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Methods of Assessing Personality
Warmth (Temperament)
Intelligence (Ability)
Emotional Stability (Temperament)
Dominance
Impulsivity
Conformity
Boldness
Sensitivity
Suspiciousness
Imagination
Shrewdness
Insecurity
Radicalism
Self-sufficiency
Self-discipline
Tension
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Theories of Personality

• Trait Theories
• Eysenck relied more on deductive methods he
  identified three, bipolar, superfactors, or types
• Extraversion (vs. introversion) Eysenck
  considered extraversion a trait with substantial
  biological roots (variations in cortical arousal)
  
• Neuroticism (vs. stability)
• Psychoticism (vs. superego)
• All three factors have biological/genetic
  foundations

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Theories of Personality

• Psychoanalytic Theories
• Sigmund Freud
• Focus is on unconscious mental forces and the
  impact of psychosexual development on personality
  formation and behavior
• Freud believed personality solidified early in
  ones life (usually by age 6) and emerged from
  the dynamic interplay between ones environment
  and intrapsychic forces
• Structure of the Mind
• Id - Seeks immediate gratification operates
  according to the Pleasure principle
• Superego Represents social standards of right
  and wrong (sense of morality) derived largely
  from parental interactions
• Ego - Mediates between the urges of the Id and
  Superego operates according to the Reality
  principle
• Personality is largely determined by the unique
  distribution of ones id, ego, and superego.

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Theories of Personality

• Sigmund Freud
• Behavior is driven by unconscious forces
  (dynamics of personality)
• Instincts
• Sex
• Aggression
• Anxiety
• Defense mechanisms represent the various ways
  individuals seek to manage their unconscious
  anxiety and may become fixed manifestations of
  ones personality
• Exodus 37-416 Moses resistance to Gods call
  on his life implementation of defense mechanisms
  until he finally laments to God please send
  someone else.
• Arrested development (i.e., fixation) at any
  phase of psychosexual development will produce
  specific personality features

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• Freuds Psychosexual Development

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Theories of Personality

• Psychoanalytic Theories
• Alfred Adler
• Adler believed that all psychological phenomenon
  were unified with the individual in a self
  consistent manner (i.e., Style of Life)
• Ones Style of Life included an individuals
  singular, unifying life goal as well as a
  persons manner of self-expression and
  self-understanding
• Striving for Superiority - universal drive to
  adapt, improve oneself, and master lifes
  challenges (the dynamic force of personality).
• Compensation - efforts to overcome a sense of
  inferiority by developing ones abilities.
• Inferiority complex - exaggerated feelings of
  weakness and inadequacy

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Theories of Personality

• Psychoanalytic Theories
• Erik Erikson
• Proponent of ego psychology focused less on
  unconscious forces and more on the unifying and
  synthesizing function of the ego
• The ego is composed of three facets
• Body ego how one views him/herself physically
• Ego ideal ones self image in comparison to
  some standard or ideal
• Ego identity how one perceives him/herself in a
  variety of social roles
• According to Erikson the ego develops through a
  series of eight psychosocial developmental stages
  that follow an epigenetic principle
• Personality emerges from the unique way an
  individual navigates and integrates each
  developmental stage and its accompanying
  psychosocial task

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Stages of Psychosocial Development
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Theories of Personality

• Linear Biometric Theory (Poppins, 1970)
• Extremely brief administration and scoring
  protocols
• Sensitive to gender differences
• Readily interpretable trait-based constructs
• Caution regarding client reaction to
  characterizations
• Sensitive to change across the lifespan

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Assessing Personality

• How would you assess personality
• Objective techniques
• Cattell
• 16PF (16 Personality Factors), CAQ (Clinical
  Analysis Questionnaire)
• Eysenck
• MPI (Maudsley Personality Inventory) or EPI
  Eysenck Personality Inventory)
• MMPI-2, NEO PI-R, CPI (California Personality
  Inventory), PAI (Personality Assessment
  Inventory), MCMI-III (Millon Clinical Multiaxial
  Inventory), etc.
• Projective Techniques (Projective hypothesis)
• Rorschach, TAT (Thematic Apperception Test), Hand
  Test, Projective Drawings (e.g.,
  house-tree-person)

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• Consider the shape you find most appealing
  consider both form and color

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You love a free and spontaneous life. And you
strive to enjoy every moment, in accordance with
the motto "You only live once." You are very
curious and open about everything new. You thrive
on change. Nothing is worse than when you feel
tied down. You experience your environment as
being versatile and always good for a surprise.
You demand a free and unattached life for
yourself that allows you to determine your own
course. You have an artistic bent in your work or
leisure activities. Your urge for freedom
sometimes causes you to do exactly the opposite
of what is expected of you. Your lifestyle is
highly individualistic. You would never follow
trends. On the contrary, you seek to live
according to your own ideas and convictions, even
if this means swimming against the tide.
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• How accurate was the test
• Projective techniques (Rorshach, TAT, CAT)
• Objective techniques (MMPI-2, NEO PI-R, MCMI-III)

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Ethical Legal Issues in Assessment

• Ethical Codes
• Ethical codes serve to
• Educate members about sound ethical conduct and
  guide the fields standard of care
• American Counseling Association (ACA)
• American Association of Christian Counselors
  (AACC)
• Provide a mechanism for professional
  accountability
• Catalyze the refinement and improvement of
  clinical practice
• Laws
• Ohio Revised Code (ORC)
• Ohio Administrative Code (OAC)
• Divine Accountability
• Love the Lord your God with all your heart and
  with all your soul and with all your mind. This
  is the first and greatest commandment. And the
  second is like it Love your neighbor as
  yourself. All the Law and the Prophets hang on
  these two commandments.
  
• Matthew 2237-40, NIV

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Ethical Legal Issues in Assessment

• American Counseling Association
• Section E Evaluation, Assessment, and
  Interpretation
• General
• Appraisal Techniques
• Assessment is to be objective and interpretable
  in either comparative or absolute terms
• Applies to test and non-test data
• Client Welfare
• Promotion of client welfare in all aspects of
  testing
• Do not misuse or allow others to misuse results
• Respect the clients right to access the results,
  interpretations, and bases for conclusions
• Competence to Use and Interpret Tests
• Limits of Competence
• Counselors recognize their limits and practice
  within their scope of training
• Counselors are familiar with reliability,
  validity, standardization, standard error of
  measure, and proper application of any technique
• Appropriate Use
• Counselors are responsible for application,
  scoring, interpretation, and use of testing
• Decisions Based on Results
• Counselors involved in client related
  decision-making have a thorough understanding of
  measurement, validation criteria, test research,
  development, and guidelines for use
• Accurate Information

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Ethical Legal Issues in Assessment

• American Counseling Association
• Section E Evaluation, Assessment, and
  Interpretation
• Informed Consent
• Explanation to clients
• Prior to assessment, counselors explain the
  nature and purpose of testing and use of results
  in language understandable to client (or
  guardian)
• Recipients of Results
• The examinees welfare, explicit understanding,
  and prior agreement determine the recipients of
  test results. Counselors include accurate and
  appropriate interpretations with any release of
  individual or group test results.
• Release of Information to Competent Professionals
• Misuse of Results
• Counselors do not misuse results and seek to
  prevent others from doing so
• Release of Raw Data
• Client consent must be obtained
• Only release to persons qualified to
  interpret/apply the information
• Proper Diagnosis of Mental Disorder
• Proper Diagnosis
• Assessment techniques (including interviews) used
  to make client care decisions are carefully
  selected and appropriately used
• Cultural Sensitivity
• Counselors understand the role culture plays in
  defining and diagnosing a disorder

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Ethical Legal Issues in Assessment

• American Counseling Association
• Section E Evaluation, Assessment, and
  Interpretation
• Test Selection
• Appropriateness of Instruments
• Consideration of validity, reliability,
  psychometric limitations, and appropriateness
• Culturally Diverse Populations
• Counselors avoid tests incompatible with clients
  culture (socialization, cognitive patterns)
• Conditions of Test Administration
• Administration Conditions
• Tests are administered under standard conditions
  departures from this are noted
• Computer Administration
• Counselors remain responsible for results even
  when computers are employed
• Unsupervised Test-Taking
• Counselor provides adequate supervision of
  testing (unless test does not require)
• Disclosure of Favorable Conditions
• Inform client of optimal test conditions
• Diversity in Testing
• Standardization Sample
• Counselors are cautious about making
  interpretations for persons of diverse groups not
  represented in the standardization sample (age,
  color, culture, disability, ethnic group, gender,
  race, religion, sexual orientation, and SES)

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Ethical Legal Issues in Assessment

• American Counseling Association
• Section E Evaluation, Assessment, and
  Interpretation
• Test Scoring and Interpretation
• Reporting Reservations
• Counselors note concerns about validity or
  reliability of outcomes due to administration
  oddities or inappropriateness of norms
• Research Instruments
• Counselors exercise caution when interpreting
  psychometrically questionable tests
• Testing Services
• Counselors are ultimately responsible for results
  obtained from testing services
• Automated test services are considered
  professional-to-professional consultation
• Test Security
• Maintenance of Test Integrity
• Counselors do not inappropriately reproduce,
  modify, or release test materials
• Obsolete Tests and Outdated Items
• Obsolete Data and Results
• Counselors do not use and attempt to prevent the
  use of outdated testing or results
• Test Construction
• Test Development
• Counselors use contemporary psychometric
  standards when developing new instruments

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Ethical Legal Issues in Assessment

• Is this ethical behavior
• A private practitioner administers a personality
  test to all of his clients. He carefully explains
  the purpose of the test and how the results will
  be used in the therapeutic process. His
  technical training and years of experience with
  the test enhance his ability to interpret it.
• A school counselor tells the parents of a third
  grader that their child's high achievement in the
  classroom coupled with superior scores on the
  Wechsler Intelligence Scale for Children-Revised
  (WISC-R) predicts success if the child is
  advanced a grade above his age level, offering
  more stimulation. When the parents asked
  follow-up questions regarding the recommendation
  it became apparent the counselor only vaguely
  understood how WISC-R scores were derived and the
  specific abilities they represent.

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Ethical Legal Issues in Assessment

• Is this ethical behavior
• The manager of an employment agency asks her
  counseling staff for advice on the purchase of a
  new test of manual dexterity currently being used
  by numerous other agencies in their clinical
  assessments. The counselors evaluate the test
  manual and advise against purchasing the test
  because there is limited evidence supporting the
  tests predictive validity.
• A counselor administers a newly developed ability
  test to a prospective college student. The test's
  predictive validity has not been established. In
  interpreting the scores, the counselor does not
  inform the student about the test's limitations
  and proceeds to draw inferences from the test
  results about the student's chances for success
  in college.

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Ethical Legal Issues in Assessment

• Is this ethical behavior
• A student completed a battery of tests at a
  university placement office. Approximately two
  weeks later he was mailed a report outlining the
  tests he had completed and gave percentile scores
  for each. The materials provided very basic
  descriptions of what each scale meant and
  included the therapists placement
  recommendations based on the observed results.
  The student disagreed with the findings and
  followed up with his academic advisor.

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Ethical Legal Issues in Assessment

• Is this ethical behavior
• A therapist trained in the administration and
  interpretation of MMPI-2s was asked by a local
  police department to screen incoming applicants
  and provide recommendations about their capacity
  to function on the force. Although the clinician
  found that, based on MMPI-2 scale elevations, a
  disproportionate number of minority clients were
  unfit for the demands of law enforcement she
  remained committed to treating all applicants
  (minority and majority clients) equally and
  refused to adjust her interpretations based upon
  an individuals racial/ethnic status she
  considered doing so a breech of the tests
  integrity that would render all profiles
  essentially equal and jeopardize the instruments
  ability to objectively evaluate someones
  capacity.

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Ethical Legal Issues in Assessment

• Is this ethical behavior
• A counselor was approached by a denomination to
  evaluate a candidate readiness for ordination.
  The clinician was given latitude by
  denominational leadership to select instruments
  she though best for assessing potential moral,
  occupational, and/or personal qualities that
  might hinder the individuals ability to minister
  effectively (they were interested in the
  candidates readiness to enter ministry.) The
  counselor administered a battery of personality
  and psychopathology measures and was surprised to
  find how many aspiring pastors obtained
  significant elevations on certain measures of
  pathology. Although surprised by this finding,
  she interpreted the tests according to their
  appropriate protocols and, after reviewing the
  results with each candidate, released (with a
  signed release of information) her report and the
  corresponding test profiles to the denomination
  for review and retention.

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Ethical Legal Issues in Assessment

• Ohio Administrative Code
• 4757-5-01 Code of Ethics
• (F) Use of Assessment
• Exact duplication of ACA code of ethics
• 4757-6-01 Reports prepared for court review
• (C)
• Counselors should remain current in their
  knowledge of data collection methods
• (E)
• Counselors must be aware diversity issues impact
  on objective evaluations
• (G)
• Counselors may be asked to critique the
  assumptions and methodologies about another
  mental health professionals methods
• (J)
• Will use multiple methods, if necessary, to
  gather data

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Ethical Legal Issues in Assessment

• Ohio Administrative Code
• 4757-13-01 Educational requirements for admission
  to the examination for professional counselor
• 11 core competency areas are defined by the state
• (A) (1) (d) (ix) Appraisal of the individual
  through testing individual and group
  psychological and educational testing and the
  study of individual differences with
  consideration of ethnic, cultural, and gender
  factors
• 4757-11-01 Denial, suspension, revocation, of
  license Disciplinary action
• (B) Violated any provision of the code of
  ethical practice or professional conduct or
  committed any other violation of professional
  behaviour contained in the rules
• (C) (18) failure to report any alleged
  violations of this act or rules adopted under it.

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Ethical Legal Issues in Assessment

• American Association of Christian Counselors
• 1-530 Ethics in Testing, Assessment, and Clinical
  Evaluation
• General
• Therapists conduct evaluations commensurate with
  their level of training
• Clinicians avoid (1) incompetent/inaccurate
  evaluations, (2) unnecessary or excessive
  (financial) testing, and (3) unauthorized
  practice of testing
• 1-531 Use of Appropriate Assessment
• Counselor use appropriate assessments, administer
  them properly, and have an adequate knowledge of
  the instruments psychometrics
• 1-532 Reporting and Interpreting Results
• Findings are reported in a comprehendible and
  objective manner
• Potential bias in the results and recommendations
  are duly considered
• Cultural factors (broadly defined) are weighed
• Uncertain findings will be communicated in
  tentative language
• James 512 Above all, my brothers, do not swear
  not by heaven or by earth or by anything else.
  Let your Yes be yes, and your No, no, or you
  will be condemned

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Switching Gears
Image taken from http//www.ignorancia.org/img_p
age.php?image76
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Statistical Considerations

• Categories of Statistics
• Descriptive
• Measures of Central Tendency
• Mean
• The average score in a data set sometimes
  referred to as the arithmetic mean
• Median
• The score falling exactly in the middle of a
  distribution
• Easier to identify when there is an odd number of
  scores must interpolate when there are an even
  number of scores
• Mode
• The most frequently occurring score in a data set
• Measures of Variability
• Range
• Standard deviation
• Conceptually, the standard deviation (SD)
  represents the average amount each individual
  score differs from the mean of the group
• Inferential

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Descriptive Statistics

• Calculations
• Mean
• 20, 21, 28, 24, 25, 27, 25, 22, 24, 26, 24
• 20, 21, 28, 24, 25, 27, 25, 22, 24, 26, 24
• Median
• 20, 21, 28, 24, 25, 27, 25, 22, 24, 26, 24 (Odd
  number of scores)
• 20 21 22 24 24 24 25 25 26 27
  28
• 20, 21, 28, 24, 25, 27, 25, 22, 24, 26, 24, 31
  (Even number of scores)
• 20 21 22 24 24 24 25 25 26 27
  28 31
• Mode
• 20 21 22 24 24 24 25 25 26 27
  28

, 114, 121
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Shapes of Distributions
Normal Distribution

• Mean Median Mode
• Symmetrical about midpoint
• Tails approach X axis, but do not touch

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Normal Distribution

• The normal curve is symmetrical
• One SD to either side of the mean contains 34 of
  area under curve
• 68 of scores lie within 1 standard deviation
  of mean

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Normal Distribution
www.hawcc.hawaii.edu/.../ Notes/Lesson431.htm
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Normal Distributions
www.southalabama.edu/.../ lectures/lec15.htm
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Shapes of Distributions

• The tail tells the tale

www.southalabama.edu/.../ lectures/lec15.htm
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• Correlation coefficient

r 0.5 r2 0.25
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Statistical Considerations

• Reliability
• Reliability is a property of the scores obtained
  when the test is administered to a particular
  group of people on a specific occasion and under
  certain conditions.
• All types of measurement (instrumentation)
  involve some level of error
• Unreliability is the result of measurement errors
  that may be reflective of temporary changes in an
  individuals internal states or properties of the
  instrument itself.

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Statistical Considerations

• Reliability
• Potential Sources of Error in Psychological
  Instrumentation/Measurement
• Method Error
• Errors related to researchers design or
  execution flaws
• Examples nonstandardization, scoring problems,
  calculation errors, differential conditions,
  sample irregularities, etc.
• Trait Error
• Errors introduced by participant differences that
  substantively impact research outcomes
• Examples Participant bias, participant health,
  self-selection errors (e.g., personality), IQ,
  etc.
• Random Error (McBurney, 2001)
• Errors related to the influence of unpredictable
  factors or some unknown independent variable
• Examples seating arrangement (participant
  placement), disruption to testing, ordering
  effects, etc.
• Systematic Error (McBurney, 2001)
• Errors associated with the presence of some
  systematic bias (most serious when associated
  with the manipulation of the independent
  variable)
• Examples typographical error on assessment, use
  of a faulty scoring program, nonstandardized
  procedure employed by researcher, etc.

63
Statistical Considerations

• Classic Reliability Theory
• Observed test scores are assumed to be composed
  of true scores and unsystematic error scores
• (S2obs S2tru S2err).
• Reliability is the ratio of true score variance
  to observed score variance this can be
  algebraically expressed as
• Reliability estimates range from 1.00 (perfectly
  reliable) to .00 (total unreliability)

64
Statistical Considerations

• Reliability Coefficients
• Test-Retest Reliability
• The test-retest coefficient (coefficient of
  stability) measures reliability by correlating
  scores obtained by the same group of people on
  the same test at two points in time.
• The time interval between test and retest greatly
  affects the test-retest coefficient ( time h r
  difference in conditions
• h time r h difference in conditions)
• Parallel Forms Reliability (Alternate Forms
  Reliability)
• A parallel forms coefficient (coefficient of
  equivalence coefficient of stability and
  equivalence) is determined by correlating scores
  from equivalent test forms and is able to control
  for both error due to differing administration
  times and error do to different forms.

65
Statistical Considerations

• Reliability Coefficients
• Internal Consistency Coefficients
• Internal consistency measures do not control for
  variations in testing conditions or times of
  administration, therefore, they are fundamentally
  different than test-retest and parallel forms
  coefficients.
• Split-half Method test items are divided into
  two sets and the separate scores are correlated.
• Kuder-Richardson Method estimates r from all
  possible split-half possibilities. (KR20 used for
  heterogenous instruments KR21 used for
  homogenous instruments)
• Coefficient Alpha this general formula is
  capable of producing r values when test items are
  scored other than 0 and 1 (therefore it can
  accommodate weighting).
• Interscorer Reliability
• Interscorer reliability (interrater reliability)
  is used when subjective evaluations are made in a
  scoring process scores between judges are
  correlated to determine reliability.

66
Statistical Considerations

• Variability and Reliability
• Adding questions of similar content and
  difficulty can increase test reliability.
• Reliability will increase when a heterogeneous
  group is used as the sample.
• Standard error of measurement (SEM) is an
  estimate of the average error in the
  approximation of a score.
• The standard deviation of a hypothetical infinite
  number of administrations of a test
• Serr S 1 r11

67
Statistical Considerations

• Validity
• Validity is the extent to which a test measures
  what it was designed to measure.
• A test can have multiple validities at the same
  time.
• Construct Validity refers to how accurately an
  instrument measure the theoretical construct (or
  concept) it purports to assess
• Convergent Validity
• Discriminate Validity
• Evidence for Construct Validity
• Expert judge
• Internal consistency analysis
• Studies
• Correlation with similar and different criterion
  measures
• Indepth questioning of respondents

An instrument should have high correlations with
tests or measures assessing the same/similar
construct (convergent validity) and low
correlations with measures assessing
opposite/different constructs (discriminate
validity).
68
Statistical Considerations

• Validity
• Content Validity refers to how accurately the
  content of a test (through its responses)
  represents the total domain of the construct
  under examination
• Most often used in conjunction with measures of
  achievement
• Criterion Validity test scores from a group are
  compared with that same groups performance in
  some criterion-specific area (e.g. GPA, mental
  capacity, productivity)
• Concurrent Validity
• Predictive Validity
• Standard Error of Estimate
• Face Validity

69
Statistical Considerations

• Factors Affecting Criterion-related Validity
• Group Differences
• Validity coefficients tend to be smaller in
  homogeneous groups.
• Cross-validation will lead to a more accurate,
  but typically smaller validity coefficient.
• Test Length
• Within limits, longer tests with heterogeneous
  groups tend to increase validity coefficients.
• Criterion Contamination
• Improper methodologies can lead to contamination
  (invalidation) of the criterion (e.g. failing to
  utilize blind or double-blind procedures).
• Incremental Validity
• Refers to how much a particular test can add to
  predictive validity.