Combined evaluations of competency to stand trial (CST) and mental state at the time of the offense (MSO) should be incorporated into research methodology to more closely mirror clinical practice. This is the bottom line of a recently published article in Law and Human Behavior. Below is a summary of the research and findings as well as a translation of this research into practice.

Featured Article | Law and Human Behavior | 2017, Vol. 41, No. 3, 217-229

Combined Evaluations of Competency to Stand Trial and Mental State at the Time of the Offense: An Overlooked Methodological Consideration?


Lauren Kois, John Jay College and the Graduate Center, City University of New York
Preeti Chauhan, John Jay College and the Graduate Center, City University of New York
James M. Wellbeloved-Stone, University of Virginia
Janet I. Warren, University of Virginia


Combined evaluations of competency to stand trial (CST; competency) and mental state at the time of the offense (MSO; sanity) frequently co-occur. However, most research examines the 2 as discrete constructs without considering 4 potential combined evaluation outcomes: competent-sane, incompetent- sane, competent-insane, and incompetent-insane. External validity can be improved if research more closely mirrored practice. It may be incorrect to assume incompetent defendants are similar across CST-only and combined evaluations, and insane defendants are similar across MSO-only and combined evaluations. Using a sample of 2,751 combined evaluations, we examined demographic, clinical, offense, evaluation, and psycholegal characteristics associated with evaluators’ combined evaluation opinions. Multinomial regression analyses revealed older defendants were more likely to be opined incompetent- insane. Defendants with psychotic disorders were more often opined insane, regardless of competency status. Affective diagnoses predicted competent-insane opinions. Developmental disorders were closely related to incompetence, regardless of sanity status. Defendants with organic disorders tended to have global psycholegal impairment, in that they were more often opined incompetent-insane, incompetent- sane, or competent-insane, relative to competent-sane. Prior hospitalization predicted competent-insane relative to competent-sane opinions. Defendants not under the influence of a substance during the offense or with no prior convictions were more likely to be opined insane, regardless of competency status. We interpret these findings in light of psycholegal theory and provide recommendations for research and practice. Collectively, results suggest incorporation of combined evaluations into CST and MSO research is an important methodological consideration not to be overlooked.


forensic assessment, competency to stand trial, mental state at the time of the offense, insanity, combined evaluation

Summary of the Research

“Evaluators regularly conduct combined evaluations of competency to stand trial (CST, competency) and mental state at the time of the offense (MSO, sanity). In their survey of U.S. pretrial forensic services, Grisso, Cocozza, Steadman, Fisher, and Greer found referral and evaluation processes for CST and MSO were similar and evaluators frequently conducted evaluations of both referral questions simultaneously in most states. Researchers have documented the frequency of these combined evaluations, with estimates occurring up to 100% of the time in study samples. However, the research literature most often examines correlates of CST and MSO independently, instead of examining them in the context of the four potential combined evaluation opinions or outcomes— competent-sane, incompetent-sane, competent- insane, and incompetent-insane. This brings to question the external validity and generalizability of this body of research, in that research thus far does not usually mirror clinical practice.” (p. 217)

“CST and MSO are strongly associated, although the correlation is not perfect. Indeed, Chauhan et al. found correlates of CST and MSO differed across CST-only, MSO-only, or combined evaluations. Furthermore, forensic evaluators in their study more often opined defendants incompetent in CST-only evaluations (36.6%) compared to combined evaluations (13.8%) and more often opined defendants insane in combined evaluations (15.0%) relative to MSO-only evaluations (12.2%), although the latter effect size was small. Still, taken together, research suggests defendants, evaluation processes, and CST and MSO opinions may be fundamentally different across singular and combined evaluations, and we cannot assume base rates and correlates of CST and MSO remain consistent regardless of the referral question and clinical inquiry implemented to address them.” (p. 218)

“Our literature review suggests base rates and correlates of CST and MSO may vary according to a sample’s composition of singular and combined evaluations. This provides further evidence that, with combined evaluation samples, CST and MSO outcomes should be examined according to the four evaluation outcomes, rather than competent versus incompetent and sane versus insane. To shed light on this methodological consideration, we examined which demographic, clinical, offense, evaluation, and psycholegal characteristics are correlated with the four definitive outcomes of combined evaluations. Consistent with the literature, we hypothesized clinical and psycholegal impairment would demonstrate the most robust relationships with opinions of incompetent-sane, competent-insane, and incompetent-insane as compared to competent-sane.” (p. 219)

“At least 282 [evaluators] submitted 5,998 joint evaluations for this study between 1990 and 2005. Note that 1.7% (n =104) of cases were missing evaluator identification numbers, so the number of evaluators is likely larger. The number of evaluations conducted by each evaluator ranged from 1 to 922 with a mean of 21.00 (SD 80.03). Five evaluators contributed more than 260 cases (3 SDs above the mean) in our study. Therefore, we randomly selected the mean number of cases (n=21) for inclusion for each of these evaluators and removed all cases with missing evaluator identification. This brought our sample size to 3,371 joint evaluations.” (p. 220)

“Guided by our results, we believe combined evaluations of CST and MSO are unique relative to CST-only or MSO-only evaluations and should be examined accordingly. Study highlights include age predicted incompetentinsane outcomes; psychotic disorders were more often associated with insanity, while developmental disorders were more often associated with incompetence; organic disorders were linked to global psycholegal impairment; and defendants who were not under the influence at the time of the offense and who did not have prior convictions were more often opined insane. Importantly, study variables did not always predict consistent CST or MSO opinions across the four outcomes: the only variable to do so was diagnosis of an organic disorder.” (p. 227)

Translating Research into Practice

“With respect to practice implications, we found evaluators are finding defendants incompetent but still opining on defendants’ MSO status on the FEIS, although we do not know whether or not evaluators included both opinions in their written reports for the court. Along with Bush, Connell, and Denney (2006), we recommend that when evaluating both psycholegal questions, evaluators
submit two separate reports to the court, accompanied by a message explaining the reports are kept separate so as not to violate defendants’ rights from self-incrimination. Combined evaluation reports may create important ethical and legal issues currently underaddressed in the literature. For instance, is it incriminating for an evaluator to note, in a CST report, whether or not defendants
were also evaluated for MSO? At present, there is no consensus or standard protocol for opining combined evaluation outcomes, and we are unsure of how evaluators typically proceed in combined evaluations when they believe a defendant is incompetent. Our missing opinion data could suggest evaluators vary in this process. According to the American Bar Association, “Existing professional ethics boards and committees should develop specific criteria and special review procedures designed to address the ethical questions that may arise when mental health professionals participate in the criminal process” (American Bar Association, 2016, Standard 7-1.6[b], “Joint professional obligations for improving the administration of justice in criminal cases involving individuals with mental disorders”). Combined evaluation issues require further contemplation by our field.” (p. 227)

“This research, in conjunction with others’ work, begins to illuminate the complexities of combined CST and MSO evaluations. As it stands, the nature of these evaluations is largely overlooked in the literature, and there are still many questions to pursue in order to develop a comprehensive understanding of the intricacies of CST and MSO research and practice. On a broader level, this study encourages researchers to carefully consider external valid-ity (meaning, true practice) when conceptualizing clinical study designs. Moving forward, we hope researchers and practitioners consider the methodological implications of combined evaluation structures in their work.” (p. 228)

Other Interesting Tidbits for Researchers and Clinicians

“Our findings indicate we cannot assume (1) defendants opined competent-sane in combined evaluations resemble those who are opined competent or sane in solitary CST or MSO evaluations (or similar patterns), and (2) there is no difference between defendants opined competent-sane and competent-insane, and no difference between defendants opined incompetent-sane and incompetent- insane. Assuming “pure” CST or MSO samples may set the stage for methodological confounds (e.g., evaluation type) that cloud the true nature of CST and MSO research findings. These findings highlight the need for further research to attend to the complexity of combined evaluations and the impact they may have on evaluation outcomes and the related research.” (p. 227)

“We encourage researchers to replicate our study across jurisdictions. We cannot assume our results are typical or if they will generalize to other forensic systems. Although Grisso et al. found more similarities than differences among individual states’ pretrial forensic services, divergence in referral base rates, legal criteria, and evaluator and defendant characteristics will likely influence evaluation outcomes. Past research that incorporated a subset of our data identified both inter- and intrastate differences in these domains.” (p. 227)

Authored by Kenny Gonzalez

Kenny Gonzalez is currently a master’s student in the Forensic Psychology program at John Jay College. His main research interest include forensic assessment, specifically violence risk. In the future, Kenny hopes to obtain a Phd in clinical forensic psychology and pursue a career in academia and practice.