Criminal Defense: What is ACH?

Matters of criminal defense are posed with one critical issue. The issue of two very distinctive adversarial views, each of which can be framed as hypotheses. In the courtroom, each of the opposing hypothesis is supported with evidence and arguments by the respective sides. The presented evidence along with skilled arguments supporting each hypothesis is then decided upon by the judiciary. In some cases, one hypothesis gains considerable weight over the opposing hypothesis, and the opposing side succumbs to the demands of the prevailing hypothesis’ proponent. This recurring courtroom behavior is undeniably similar to the historical use of Analysis of Competing Hypotheses (ACH).
Matters of criminal defense are posed with one critical issue. The issue of two very distinctive adversarial views, each of which can be framed as hypotheses. In the courtroom, each of the opposing hypothesis is supported with evidence and arguments by the respective sides. The presented evidence along with skilled arguments supporting each hypothesis is then decided upon by the judiciary. In some cases, one hypothesis gains considerable weight over the opposing hypothesis, and the opposing side succumbs to the demands of the prevailing hypothesis’ proponent. This recurring courtroom behavior is undeniably similar to the historical use of Analysis of Competing Hypotheses (ACH).

Analysis of Competing Hypotheses “is an analytic process that identifies a complete set of alternative hypotheses, systematically evaluates data that is consistent and inconsistent with each hypothesis, and rejects hypotheses that contain too much inconsistent data.” ACH is an eight step process used to enhance analysis by mitigating the cognitive limitations of an analyst and increase the probability of the most optimal outcome. The eight steps of ACH in chronological order are: identify all possible hypotheses, make a list of significant evidence and arguments, prepare a matrix to analyze the "diagnosticity" of evidence, draw tentative conclusions, refine the matrix, compare your personal conclusions about the relative likelihood of each hypothesis with the inconsistency scores, report your conclusions and identify indicators.

ACH was developed by Richard J. Heuer Jr., a 45-year veteran of the Central Intelligence Agency (CIA). ACH has been informally employed by the intelligence community since the 1970s. ACH was developed to help analyst produce the best available information from uncertain data. Initially ACH used by the CIA as the core element in an interagency Deception Analysis course during the Reagan administration. As a result ACH proved instrumental in the development of intelligence analysis methodology. Eventually, with the help of the Palo Alto Research Center (PARC), Heuer was able to develop the PARCH ACH 2.0.5 software for use within the intelligence community.

There are many benefits of utilizing ACH and applying an ACH matrix to complex situations. It is widely believed ACH helps overcome cognitive biases. Construction of a matrix demonstrates to the decision maker or other analysts the sequence of rules and data that led to the conclusion. ACH is not without its weaknesses though. ACH is susceptible to the use of false or intentionally deceiving intelligence and information. The process of creating an ACH matrix can also be time consuming and complex when dealing with a multitude of variables.

Today ACH is used by analysts in various fields who make judgements that entail a high risk of error in reasoning. ACH is used to help mitigate any present cognitive limitations related to prescient intelligence analysis and ensure the best possible outcome is achieved. Analysis of intelligence is often a high stakes game for analysts, attorneys and investigators. In these seemingly difficult situations, it is best for decision makers to eschew their emotionally charged and potentially biased analysis and recommendations.

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