Chapter 3: Assessment and Diagnosis
Involves a series of steps designed to gather info or data about a person and their environment in order to make
decisions about the nature, status, and treatment of psycho problems. Typically begins with a set of referral questions
developed in response to a request for help (usually from the person or someone close). These initial Qs help det the
goals of the assessment and the selection of appropriate psych tests or measurements.
Goals of Assessment
3.1 Understand the goals and uses of clinical assessment.
Psychologist decided which procedures and instruments to administer, which include measures of bio function,
cognition, emotion, behaviour, and personality style. Patient’s age, medical condition, and description of their
symptoms strongly influence the tools selected for assessment, but the psychologist’s theoretical perspective also
affects the scope of the assessment.
Once an assessment has been completed and all the data collects, the psychologist integrates the findings to develop
preliminary answers to the initial questions; typically sharing them with the patient and family members involved. Other
health care providers part of the referral/assessment could also receive the results with the patient’s clearance.
Sometimes this has a therapeutic effect. As ppl begin to understand their emotions, behaviours and the links
between them, their symptoms tend to improve, at least temporarily. Screenings can help identify ppl who have
problems but may not be aware of them or reluctant to mention them and/or those who may need further evaluation.
At the end of the treatment, clinical assessment can measure a patient’s progress or the outcomes of intervention.
Identify potential psych problems or predict the risk of future problems if someone is not referred for further
assessment or treatment. All members of a group are given a brief measure for which some identified cut-off score
indicated the possibility of significant problems. In most cases, when indivs score above a certain cut-off number on a
screening instrument, a more thorough evaluation can determine the nature and extent of their difficulties.
Because many ppl with psych probs are more likely to see their physician than a mental health professional, brief
methods for screening patients in medical settings have been developed.
To evaluate the usefulness of any particular screening measure, psychologists look for instruments that have strong
sensitivity and specificity. Sensitivity describes the ability of the screener (or the instrument) to identify a problem that
actually exists. Sepcificity indicated the percent of the time that the screen accurately identifies the absence of a
False positives occur when the screening instrument indicates a problem when no problem exisits.
False negatives occurs when the screening toold suggest no depression when the patient is depressed.
Good screening tools have high specificity and sensitivity, but low false positive and false negative rates.
Diagnosis and Treatment Planning
Diagnosis refers to the identification of an illness. In psych, it requires the presence of a cluster of symptoms.
Typically, diagnosis is made after a clinical interview with the patient. Differential Diagnosis is the term used when
clinicians attempt to determine which diagnosis most clearly describes the patient’s symptoms.
Using different assessment instruments, the clinician gathers data from the patient and often other sources (parents,
partners, and teachers) to make the diagnosis or diagnoses that fit the patient. Diagnostic Assessments are more
extensive than screens and are designed to provide a more thorough understanding of a person’s psychological
status. Accurate diagnosis are critical for planning appropriate treatment. They are often needed for insurance
companies to reimburse a psychologist or a healthcare provider.
A clinical assessment that leads to a diagnosis usually includes the evaluation of symptom and disorder severity,
patterns of symptoms over time, and the patient’s strengths and weaknesses. It may also include results from
personality tests, neuropsychological tests, and/or a behavioural assessment. Behavioural psychologists also conduct
a functional analysis of symptoms, which identifies the relations between situations and behaviours to aid in devising a
Clinical assessments can be repeated at regular intervals during treatment to evaluate a patient’s progress. Outcome
evaluations help us know whether patients are getting better, when treatment is “finished”, or when modification to an
approach that is no achieving its aims is necessary. This assessment may include evaluating patient satisfaction and
providing data to support the marketing of treatment programs.
To be useful, the same measures must be administered consistently over the course of treatment. The indiv measure should rep a range of outcomes (e.g. symptom severity, treatment satisfaction, ability to function, and quality of life.)
When possible, it should go beyond the patient’s view point to include the therapist’s perspective and perhaps that of
family members etc. They must be reliable and valid. To evaluate whether treatments have the desired effect, both the
degree of change and the patient’s actual level of functioning after treatment must be assessed. In evaluating the
outcomes of psych disorders, he goal may be to reduce symptoms and/or to eliminate the disorder.
The degree of change is generally considered in terms of clinical significance. This means that the observed change
actually is a meaningful improvement. A measure known as the Reliable Change Index (RCI) is now freq used to det
whether the degree of change from beginning to end of treatment is meaningful. Patients’ scores on various measures
after treatment are sometimes compared with scores of ppl without the disorder who have also completed the
assessment to evaluate whether symptoms and functioning have moved into the normal range.
Properties of Assessment Instruments
3.2 Name three important properties of psychological assessment instruments
The potential value of an assessment instrument rests in part on its various psychometric properties, which affect how
confident we can be in the testing results. Psychometric properties include: standardization, reliability, and validity.
To understand the results, it must be put into context. Standard ways of evaluating scores can involve normative or
self-referent comparisons (or both). Normative comparisons require comparing a person’s score with the score of a
sample of ppl who are rep of the entire pop or with the score of a subgroup who are similar to the patient being
assessed. If a person’s score falls too far outside of the normative range, we can assume that a problem exists. To
decide whether a score is too far outside the range of the normal group, we use standard deviation (SD). This is a
measure that tells us how far away from the mean a particular score is. According to statistical principles, a score that
is more than 2 SDs away from the mean is found in only 5% of the population and is considered meaningfully different
from what is normal. Must also consider the characteristics of both the patient and the group.
Self-referent Comparisons are those that equate responses on various instruments with the patient’s own prior
performance, and they are used most often to examine the course of symptoms over time. They are also used to
evaluate treatment outcome. Hope to see improvement of symptoms and quality of life.
Refers to the consistency of the instrument, or how well the measure produces the same result each time it is used. It
is assessed in many ways:
Test-retest reliability address the consistency of scores across time. Administer the same instrument twice to the
same people over some consistent interval, such as two weeks or one month. A correlation coefficient is calculated to
estimate the similarity between the scores. Correlations of .8 or higher indicate that a measure is highly reliable over
Interrater Agreement is important for measures that depend on clinician judgment. Two different clinicians administer
the same interview to the same patients.
Refers to the degree to which a test measures what it intended to measure. Construct Validity reflects how well a
measure accurately assesses a particular concept, not other concepts that may be related. Criterion Validity assesses
how well a measure correlates with other measures that assess the same or similar constructs. One type of criterion
validity: concurrent validity, assesses the rel between two measures that are given the same times. Predictive Validity
refers to the ability of a measure to predict performance at a future date.
Another issues is the accuracy of a psychologist’s predictions or conclusions at the end of the assessment process.
After all the data have been collected, a clinician is often asked to make judgement. To reach answers, clinicians can
make predictions based on statistical data or clinical observations. Clinical prediction relies on a clinician’s judgment.
Statistical prediction results when a clinician uses data from large groups of ppl to make a judgment about a specific
indiv. In general, results of predictions based on the same patient data can be very different when clinical and
statistical strategies are used, but data from more than 136 studies support the conclusion that statistical predictions
are more accurate than clinically based predictions. Statistical prediction is used in the practice of evidence-based
medicine when data are available to predict who will benefit from which treatments. Clinical Judgment is useful when
relevant statistical data do no exist and when new hypotheses need to be developed.
Developmental and Cultural Considerations
Age and Developmental status are the most important factors in terms of a clinician’s choice of assessment
techniques and instruments. The nature of the tests chosen, the normative values against which the scores are compared, the ppl involved in the testing process, and the testing environment can vary significantly depending on
whether the person to be assessed is a child, an adolescent, an adult, or an older person. Varying cognitive abilities
according to developmental status call for diff tests. Measures of psych symptoms vary across age.
The assessment process may also vary depending on the patient’s age. Wrt children, input fro parents and teachers is
essential. Wrt adults with cognitive limits, input from adults who spend time with them is useful. Illiterate children and
older ppl with ltd vision may also need help completing self-report measures. Young children with ltd attention capacity
and older adults with cognitice and/or physical limitations may also need short testing sessions with additional breaks.
The assessment process should also consider cultural factors. “Culture fair” assessments take into account variables
that may affect test performance. Translation into other languages; data from minority groups collected. Language
translation may not be sufficient, some measure of psych performance rely more on nonverbal skills.
Ethics and Responsibility
Psychologists who administer psych assessments must adhere to the American Psychological Code of Ethics. Sec 9
requires that they only administer tests for which they have received training. Only used instruments with good
reliability and validity and are appropriate for the purpose of the exam. Should not use outdated tests and must obtain
informed consent from the person whom they want to test. Informed Consent indicates that the person to be tested
understands the test’s purpose, its related fees, and who will see the results. Testing data should remain confidential
and be stored in a secure location, even those that occur vie the Internet.
3.3 List an explain the function of different types of assessment instruments
Choosing the best set of instruments depends on the goals of the assessment, the properties of the instruments, and
the nature of the patient’s difficulties. Some ask the patient to evaluate their own symptoms (self-report measures);
others require a clinician to rate the symptoms (clinician-rated measures); some assess subjective responses (what
the patient perceives) and others objective responses (observed). Some are structured (Each rec same set of
questions) and others unstructured (qs vary across patients). When a number of tests are given together, the group of
tests is called a test battery.
Consist of a conversation between an interviewer and a patient, the purpose of which is to gather info and make
judgments related to the assessment goals. Interviews can screen, diagnose, plan treatment, or provide outcome
evaluation. Conducted (un)structured.
1. Unstructured interviews – clinician decides what questions to ask and how to ask them. The initial interview
is usually unstructured, which allows them to get to know the patient and determine what other types of
assessment might be useful. It also helps them get to know each other and develop a working relationship.
At start of initial interview, education provided wrt assessment process and patient asked about their
difficulties. Qs can be open-ended, allowing the patient flexibility to decide what info to provide, or close
ended, allowing the clinician to ask for specific info about a topic. Both the presenting problem and the
clinician’s theoretical perspective guide the content and style of the questions. At the end the clinician
summarizes what has been learned and offers some guidelines about what will happen next.
Primary benefit is flexibility: can move in whatever directions seem most appropriate, following up on
the patient’s comments. Major limitation is potential unreliability. Possible that two interviewers could come to
very different conclusions about the same patient if their interviews did not include the same topics or ask the
same questions. Structured interviews minimise such problems.
2. Structured Interviews – each patient asked same standard set of questions, usually with a goal of establishing
a diagnosis. Semi-structured interviews: after the standard question, the clinician uses less structured
supplemental questions to gather additional info as needed. Structured or semi are often used in scientifically
based clinical practice and in clinical research, and they increase the reliability of the interview process.
Although a patient’s scores still rely on clinician judgement, the consistency in content and the order of
questions increases the likely hood of agreement across interviewers. Choosing one or the other depends on
the goals of the assessment, the clincian’s knowledge of and trinaing with the particular interview, and the
properties of the interview itself. Freq a more focused interview is used after an unstructured screening
interview indicates that certain diagnoses may be appropriate. Focused interviews can be useful in research settings in which it is often important to make sure that all patients in a study have similar diagnoses. These
interviews are important in clinical practice so that a provider has sufficient details about a diagnosis to design
an appropriate treatment plan. Drawback: less flexibility wrt questioning.
- measure hundreds of dimensions
1. Personality Tests – measure personality characteristics; choice of test depends on its purpose and on
whether one is assessing a healthy pop or a clinical sample.
Best known personality test: Minnesota Multiphasic Personality Investory (MMPI)
Used empirical keying to develop statistical analyses to identify items and patterns of scores that
differentiated various groups. Only those that differentiated were retained. It also included statistical
scaled to evaluate a number of test-taking behaviours. Eg Lie scale, faking good/bad scales.
A revised version MMPI-2 has 567 items and includes nine validity scales and ten clinical subscales.
Nine restructured clinical subscales were also designed to improve validity and relate more directly to
newer theories of personality. It is scored by a computer program that creates a profile that the testing
psychologist can then interpret. Serious concerns exist wrt the use of MMPI with ethnic minorities
because the test was originally standardized on white samples.
The Millon Clinical Multiaxial Inventory (MCMI) is a 175 item true-false inventory that corresponds to 8
basic personality styles, three pathological personality syndromes, and nine symptom disorders scales. It
has adequately reliability and validity and clinicians prefer it to the MMPI because it requires less time to
complete. However, the MCMI does not map onto categories of disorders as they are described in the
DSM system and the test us culturally biased.
Projective testing- emerge