Applied Fields: Forensic

Introduction

Psychological forensic assessment aims to contribute to rational problem-solving in a forensic context when judgements have to be made about conditions or consequences of human behaviour brought to (criminal or civil) court. We describe a decision-oriented model of the process of psychological assessment that can serve as a general framework for psychological assessment concerning forensic questions. Frequently asked forensic questions relate to (1) psychological problems of parental custody and contact with children after divorce, (2) credibility of witness statements, and (3) prognosis of offence recidivism.

General Concept

Modern psychological forensic assessment is conceived as an aid for optimizing forensic problem solving in a scientific process of hypotheses-testing. The assessment process can be regarded as a sequence of decisions. Decisions during planning have a crucial impact on assessment results: mistakes in planning may cause invalid results. Additionally, many decisions must be made while realizing the assessment plan and combining the data into results. Explicit rules to aid these decisions are explained and compiled in checklists by Westhoff and Kluck (1998).

This approach is in contrast to the – outdated – trait-oriented comprehensive ‘portraying’ of the personality. According to this general concept, it is not the personality that has to be evaluated, but the conditions and the course of a person's actions, or the relations between individuals, in the past, present and in the future. There are six sets of conditions influencing human behaviour: (1) environment; (2) organism; (3) cognition; (4) emotion; (5) motivation; and (6) social variables; and their interactions.

In a single case, all empirically relevant conditions and behavioural variables are checked for their contributions to the forensic question put to the psychological expert. In order to test the resulting hypotheses, different sources of information have to be selected, e.g. according to their psychometric properties. Data can be gathered from systematically planned interviews, observation of behaviour, biographical files and standardized procedures (e.g. tests or questionnaires). Assessors balance the costs of a special assessment procedure, e.g. a test, and its benefits. Of course, they take into consideration not only material, but also immaterial costs and benefits for each participant in the assessment process. A competent realization of the assessment plan requires the up-to-date knowledge and skills of a well-trained psychologist. This expert will use the most objective methods of documentation, e.g. tape recording of interviews.

Data from all relevant sources of information are weighted according to the single case and combined in order to reach a decision about each of the initial hypotheses. In a second step the outcomes of these decisions are integrated, in order to answer the forensic question(s) posed by the judicial system. The conclusions are always stated as probabilistic ‘if-then’-statements.

The structure of a psychological report according to this assessment process corresponds to the international scientific publication standards and the Guidelines for the Assessment Process (GAP) of the European Association of Psychological Assessment (Fernandez-Ballesteros et al., 2001):

• 1
  Client's question (and client)
• 2
  Psychological questions (= hypotheses)
• 3
  Plan and sequence of the investigation (including the names of all investigators, all appointments, duration and locations of meetings)
• 4
  Data
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• 5
  Results
• 6
  Recommendations and suggestions (if asked for in the client's question)
• 7
  References
• 8
  Appendix (including psychometric calculations)
• 9
  Signature (of the responsible psychologist)

Judicial System and Forensic Questions Put to the Psychological Expert

The roles and the tasks of all the participants in legal proceedings differ according to the different judicial systems in Western societies. Consequently, the questions put to forensic psychological experts, and their working conditions, differ as well. Nevertheless, there are common basic forensicpsychological concepts and methods. The following sections will deal with them. They will be illustrated by sketches of the forensic questions most frequently put to psychological experts.

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