Problem Given the number of times in which an unknown event has happened and failed: Required the chance that the probability of its happening in a single trial lies somewhere between any two degrees of probability that can be named. SECTION 1 Definition 1. Several events are inconsistent, when if one of them happens, none of the rest can. 2. Two events are contrary when one, or other of them must; and both together cannot happen. 3. An event is said to fail, when it cannot happen; or, which comes to the same thing, when its contrary has happened. 4. An event is said to be determined when it has either happened or failed. 5. The probability of any event is the ratio between the value at which an expectation depending on the happening of the event ought to be computed, and the value of the thing expected upon it’s 2 happening.

An essay towards solving a problem in the doctrine of chances. [Facsimil]

Mental health professionals are routinely called upon to assess the risk of violence presented by their patients. Prior surveys of risk assessment methods have been largely circumscribed to individual countries and have not compared the practices of different professional disciplines. Therefore, a Web-based survey was developed to examine methods of violence risk assessment across six continents, and to compare the perceived utility of these methods by psychologists, psychiatrists, and nurses. The survey was translated into nine languages and distributed to members of 59 national and international organizations. Surveys were completed by 2135 respondents from 44 countries. Respondents in all six continents reported using instruments to assess, manage, and monitor violence risk, with over half of risk assessments in the past 12 months conducted using such an instrument. Respondents in Asia and South America reported conducting fewer structured assessments, and psychologists reported using instruments more ...

International Perspectives on the practical application of violence risk assessment : a global survey of 44 countries

These Practice Guidelines for the Psychiatric Evaluation of Adults mark a transition in the American Psychiatric Association’s Practice Guidelines. Since the publication of the 2011 Institute of Medicine report Clinical Practice Guidelines We Can Trust, there has been an increasing focus on using clearly defined, transparent processes for rating the quality of evidence and the strength of the overall body of evidence in systematic reviews of the scientific literature. These guidelines were developed using a process intended to be consistent with the recommendations of the Institute of Medicine (2011), the Principles for theDevelopment of Specialty Society Clinical Guidelines of the Council of Medical Specialty Societies (2012), and the requirements of the Agency for Healthcare Research andQuality (AHRQ) for inclusion of a guideline in the National Guideline Clearinghouse. Parameters used for the guidelines’ systematic review are included with the full text of the guidelines; the development process is fully described in a document available on the APA website: http:// www.psychiatry.org/File%20Library/Practice/APA-GuidelineDevelopment-Process–updated-2011-.pdf. To supplement the expertise of members of the guideline work group, we used a “snowball” survey methodology to identify experts on psychiatric evaluation and solicit their input on aspects of the psychiatric evaluation that they saw as likely to improve specific patient outcomes (Yager 2014). Results of this expert survey are included with the full text of the practice guideline.

https://ajp.psychiatryonline.org/doi/pdf/10.1176/appi.ajp.2015.1720501

The American Psychiatric Association Practice Guidelines for the Psychiatric Evaluation of Adults

This article describes principles for developing risk category labels for criterion referenced prediction measures, and demonstrates their utility by creating new risk categories for the Static-99R and Static-2002R sexual offender risk assessment tools. Currently, risk assessments in corrections and forensic mental health are typically summarized in 1 of 3 words: low, moderate, or high. Although these risk labels have strong influence on decision makers, they are interpreted differently across settings, even among trained professionals. The current article provides a framework for standardizing risk communication by matching (a) the information contained in risk tools to (b) a broadly applicable classification of "riskiness" that is independent of any particular offender risk scale. We found that the new, common STATIC risk categories not only increase concordance of risk classification (from 51% to 72%)-they also allow evaluators to make the same inferences for offenders in the same category regardless of which instrument was used to assign category membership. More generally, we argue that the risk categories should be linked to the decisions at hand, and that risk communication can be improved by grounding these risk categories in evidence-based definitions. (PsycINFO Database Record

Communicating the results of criterion referenced prediction measures: Risk categories for the Static-99R and Static-2002R sexual offender risk assessment tools

Background Rates of violence in persons identified as high risk by structured risk assessment instruments (SRAIs) are uncertain and frequently unreported by validation studies. Aims To analyse the variation in rates of violence in individuals identified as high risk by SRAIs. Method A systematic search of databases (1995–2011) was conducted for studies on nine widely used assessment tools. Where violence rates in high-risk groups were not published, these were requested from study authors. Rate information was extracted, and binomial logistic regression was used to study heterogeneity. Results Information was collected on 13 045 participants in 57 samples from 47 independent studies. Annualised rates of violence in individuals classified as high risk varied both across and within instruments. Rates were elevated when population rates of violence were higher, when a structured professional judgement instrument was used and when there was a lower proportion of men in a study. Conclusions After controlling for time at risk, the rate of violence in individuals classified as high risk by SRAIs shows substantial variation. In the absence of information on local base rates, assigning predetermined probabilities to future violence risk on the basis of a structured risk assessment is not supported by the current evidence base. This underscores the need for caution when such risk estimates are used to influence decisions related to individual liberty and public safety.

Rates of violence in patients classified as “high risk” by structured risk assessment instruments: A meta-analysis of 49,283 participants in 140 samples

Seena Fazel

Papers

Rates of violence in patients classified as “high risk” by structured risk assessment instruments: A meta-analysis of 49,283 participants in 140 samples