PART 1 : INTRODUCTION

• Jurisdiction: Australia

PART 1: INTRODUCTION

[60.10] The Nature of Psychological Testing and Assessment

A psychological test is a sample of behaviour used to make inferences about an individual within a specific context, or to elicit signs of an underlying disposition. It is generally acknowledged that among the various mental health professionals, psychologists in particular are best equipped to administer and interpret psychological tests. Professional training programs are mandated to attend to core competencies in psychological testing and assessment in order to meet accreditation standards set by the Australian Psychology Accreditation Council, while new graduates pursuing registration through alternative training schemes must successfully sit the National Psychology Examination overseen by the Psychology Board of Australia on behalf of the Australian Health Practitioner Registration Agency. In general, assessment competencies are exclusive to psychologists (Ready & Veague, 2014).

The principles underlying the certification of psychologists, and the tests that they use, relate broadly to the concept of Psychology as a science. This is grounded in the philosophical approach of Positivism: a system recognizing only that which can be scientifically verified or which is capable of logical or mathematical proof (Beck et al, 2014). In basic terms, psychological assessment should be undertaken in the context of a coherent scientifically justifiable theory as to what question(s) the assessment will answer, how this relates to the issue or problem at hand, and using tests and measures to assist in that assessment which have a data pedigree lending confidence to the conclusions drawn from the assessment, referred to as the "psychometric properties" of the test.

Thus, when evaluating the probative value of psychological assessments, the legal practitioner should ascertain:

• whether the psychologist used a theoretically sound rationale to develop the questions to be addressed in the assessment;
• if s/he chose the right sort of test or tests to answer those questions; and,
• whether the specific test or tests chosen has been proven to provide reliable data relevant to the question at hand.

Each of these questions will be addressed in the remainder of this chapter, inclusive of the limits of confidence that may be applied to each in relation to general issues of psychological relevance as well as the specifics of individual assessment tools (tests). However, it is first necessary to discuss what is meant by "psychological assessment" and how psychologists conduct assessments to both determine the nature of the problem and derive strategies to address the problem.

[60.20] What are "Psychological Assessments"?

Psychological testing and psychological assessment are not synonymous. A psychological test is a systematic procedure for observing an aspect of a person's behaviour or performance, or the general characteristics of the person (Anastasi & Urbina, 1997). For example, a psychological test can describe a person's aptitude for a job, or their general level of intelligence. Psychological tests are based on psychological theories that consider the importance of individual differences and seek to explain them. Psychological tests are different from other tests or quizzes in that they are standardised, meaning that the materials used and the scoring methods are always the same so that the same test can be given at different times and in different locations. The same (or nearly the same) result should be able to be produced irrespective of the psychologist who is administering the test, providing the psychologist conforms to the testing procedures for the particular test and the person being tested is able to perform tasks with an equal level of competence on each occasion that testing occurs. This enables the development of norms, or what scores mean with reference to the performance of a large group of people on the same test. This is referred to as the "standardisation sample" or a "standardised score" (Groth-Marnet, 2016).

As noted above, a test may provide a sample of behaviour or a sign of an underlying disposition. Where the test is a sample of behaviour (eg working memory ability), interpretation of test performance is in terms of "criterion referencing" (eg average length of working memory), while tests providing signs of a...