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Description: What do Psychologists do in courtroom when they serve as expert witnesses? This is a huge and complicated topic so let’s focus in a bit. If a Psychologist has been asked by the court to assess an accused individual and if they use a measure or two in order to develop their opinion of that individual what would you expect to be true of those measures? Think about your answer to that question as if you were the judge in the courtroom having to decide what sort of trust or weight to put on the resulting Psychologist testimony. What would you want to see or hear? These are important questions and they should be linked to the ethics that Psychologists hold themselves to when they serve as expert witnesses in court. Once you have your thoughts/answers in order read the article linked below and see if it suggests something you did or did not include in your thinking.

Source: Courtroom psychology tests may be unreliable, study finds, Christina Larson, The Associated Press.

Date: February 16, 2020

Photo Credit:  Image by John Hain from Pixabay

Article Link:

So, did your ethical musings include the issues raised in the article and in the research, it reported upon? The issue is a very import ant one. When I lecture or write about the use of Psychological tests of any sort ion any decision-making situation, I offer the following advice. If a decision that will affect you or a loved one (or anyone) is going to me made wholly or partially on the basis of a Psychological measure or test then, ethically, the person administering the test should be able to answer two questions on the spot off the top of their head (they should be VERY familiar with the answers). First, is the measure reliable (as posed in the title of the linked article)? Second, is the measure valid (not really discussed directly in the linked article). Reliability is the extent to which a measure produces nearly exactly the same results when administered to the same people withing short periods of time. Imagine you measured something twice with the same ruler and got different results each time. If the thing being measured has not been cut or grown somehow then you should doubt the reliability of the rule (perhaps it is made of an unstable material, hyper-reactive to temperature or the like). Ether way a measure that produces different results when the thing being measured is very unlikely to have changed between assessments would suggest the measure is unreliable – basically useless. We assess the reliability of Psychological measures by measuring the same people twice over a short period of time (a few days to week) and if the results are not nearly identical (Test time 1 and Test time 2 scores correlate above 0.9 if you understand correlations where 1.0 is the highest they can go). If a measure is unreliable or produces inexplicably variable results when we do not think things have changed, then the measure should certainly NOT be used to inform decisions about people’s guilt or the appropriateness of their being hired, or permitted entrance to an educational program or anything. Those using Psychological measures, ethically, should know the reliability of their measures and be able immediately when asked, to explain how reliable the measure is. If they cannot do this, they should not be permitted to proceed with measurement or assessment. Once reliability has been established, the next ethical question concerns the validity of the measure. Validity is defined as whether the measure or test measures what it is purported to measure. Intelligence tests should measure intelligence, deviance measures should measure deviance – sounds obvious and bit stupid as a question, right? Well yes but remember, we use Psychological measures to assess things we cannot easily see directly. So, we cannot see intelligence directly, but we believe that scores on intelligence tests should predict how well children do in school (IQ tests do this pretty well) or how successful children become when they grow up (IQ tests do not do this very well if at all). So, a measure’s validity is an empirical question – a question for research and anyone using a test or measure ethically, MUST be aware of what research (lots of good research) has to say about the measures validity – the value of their expertise and their usefulness as an expert witness depends upon it. THIS is where courts struggle as answers to reliability questions are easily understood while answers to validity questions typically require much of the same expertise that the Psychologist expert witness has or claims to have and THAT is why this is a serious matter of professional ethics. OK, lecture done but remember it as you definitely need its main points at some point in your future and measures are everywhere!

Questions for Discussion:

  1. What is reliability and how do we determine if a measure is reliable?
  2. What is validity and how do we determine if a measure is valid?
  3. How should a Psychologist be assessed if he or she is being considered as a possible expert witness, particularly if they are going to talk about the results of an assessment or measure they have used? Does this apply to mother situations and to other professionals?

References (Read Further):

Garrett, B. L., & Neufeld, P. J. (2009). Invalid forensic science testimony and wrongful convictions. Virginia Law Review, 1-97. Link

Neal, T. M., Slobogin, C., Saks, M. J., Faigman, D. L., & Geisinger, K. F. (2019). Psychological Assessments in Legal Contexts: Are Courts Keeping “Junk Science” Out of the Courtroom? Psychological Science in the Public Interest, 20(3), 135-164. Link

Hiller, J. B., Rosenthal, R., Bornstein, R. F., Berry, D. T., & Brunell-Neuleib, S. (1999). A comparative meta-analysis of Rorschach and MMPI validity. Psychological Assessment, 11(3), 278. Link

Meyer, G. J., Riethmiller, R. J., Brooks, R. D., Benoit, W. A., & Handler, L. (2000). A replication of Rorschach and MMPI-2 convergent validity. Journal of Personality Assessment, 74(2), 175-215. Link

Brodsky, S. L. (2013). Testifying in court: Guidelines and maxims for the expert witness. Washington, DC: American Psychological Association. Link

Grove, W. M., & Barden, R. C. (1999). Protecting the integrity of the legal system: The admissibility of testimony from mental health experts under Daubert/Kumho analyses. Psychology, Public Policy, and Law, 5(1), 224. Link

Ritzler, B., Erard, R., & Pettigrew, G. (2002). Protecting the integrity of Rorschach expert witnesses: A reply to Grove and Barden (1999) re: The admissibility of testimony under Daubert/Kumho analyses. Link