PSICAN - Paranormal Studies and Inquiry Canada

Ghosts, Hauntings & Related Phenomena

Written by J.A. Cuddington

The Application of Analysis of Competing Hypotheses in the Research of Paranormal Occurrences - A Proposal to Stimulate Discussion

While I was serving with a Canadian Police Force, I spent nearly ten years in the role of an Intelligence Analyst.   Intelligence Analysts spend most of their time reviewing huge amounts of data and information that frequently spans months or even years.  Each bit of information must be evaluated as to its credibility and worth, then catalogued, and stored.  The information has to be able to be retrieved and processed to reduce it down to a workable assessment.  The assessment can be turned into a report that makes sense of the broad spectrum of data. . The analyst studies the available pieces of information and attempts to assemble them into a logical pattern to show meaning.  In day-to-day life what often happens, unfortunately, is that we leap to conclusions without developing sound, fact-based arguments. In intelligence analysis, the reasoning process is deliberate and formal in order to reveal the relationship between the data and the conclusion.

I became familiar with Richards (Dick) Heuer's Analysis of Competing Hypotheses or ACH.   Dick served with the Central Intelligence Agency for forty five years and worked in collection, operations, counterintelligence, intelligence analysis, and personnel security. Dick wrote several books and many articles: Psychology of Intelligence Analysis, Structured Analytic Techniques for Intelligence Analysis and developed the concept of Analysis of Competing Hypotheses.

Essentially, ACH is a tool to aid judgment on important issues requiring careful weighing of alternative explanations or conclusions. [1]

ACH consists of an eight-stage methodology consisting of basic insights from cognitive psychology, decision analysis, and the scientific method.  The effectiveness of this methodology assists analysts in avoiding common analytic pitfalls. It is particularly appropriate for controversial issues when analysts want to leave an audit trail to show what they considered and how they arrived at their judgment.  The ACH methodology can have very useful aspects when transposed to create a standardized method of testing evidence of the paranormal.

Analysts are constantly faced with the "what if" scenario.  As the future contains many possibilities, analysts will identify all reasonable outcomes and create hypotheses to simplify the possibilities from a predictive point of view and narrow their field of concentration.  The analyst will weigh the evidence against each hypothesis to asses the probability of each outcome.[2]

Intelligence analysts are faced with huge amounts of data, evidence and possibilities whereas paranormal researchers and investigators work within the parameters of collecting historical accounts, witness accounts personal experiences and data, setting them against hypotheses.  In my view, I believe that as far as paranormal investigations go, there can only be three basic hypotheses. The first hypothesis is that there is a natural explanation apparent for the occurrence. The second hypothesis is that there is no natural explanation apparent for the occurrence and thirdly, that the occurrence is unfounded.   The word hoax can have negative characterizations attached to it and may give rise to hostile reactions if it is applied to someone's claim of a haunting.   For our purposes, it would be more accurate and less volatile to refer to it as "unfounded".  This would also include not only an intentional hoax but also a situation where there are no witnesses available for interview and no personal experiences by the investigators or evidence collected.

An example of an unfounded investigation that is not a hoax could be a place that has stories and rumours attached to it over time but no documented witness accounts and no collected evidence.  The investigators attend the location but are unable to collect any evidence and do not observe any of the rumoured occurrences.  This investigation on that date can be classified as unfounded.

Let us consider the types of evidence that paranormal researchers/investigators may encounter to test against the hypotheses. Let us also keep in mind that the result is only as good as the evidence that is entered into the equation. The first might be historical documentation that contains witness accounts.  These historical accounts may not be able to be confirmed and may simply be anecdotal folklore. On the other hand, it may take the form of written records of witness accounts over a lengthy period of time.  This will give it more or less weight in the final analysis.  There are contemporaneous witness accounts that have the benefit of scrutiny by the investigator that are considered evidence. The investigator's own personal experience impartially documented will become evidence. Other forms of evidence can be light anomalies, sound anomalies, visual anomalies such as shadows or dark masses, partial and full bodied apparitions, temperature anomalies, kinetic anomalies and odour anomalies to name a few.

Dick Heuer suggested making a matrix with the hypotheses across the top and the evidence down the side and then analyze the "diagnosticity" of the evidence.  In other words, determine which pieces of evidence are most helpful in judging the relative likelihood of the hypotheses.[3]  Then carefully reconsider both hypotheses and evidence and eliminate that which has no diagnostic value.  For example, in considering the hypothesis that an occurrence is naturally occurring, having the item "Odour Anomaly" entered as a piece of evidence where there never were any odours mentioned or detected would not have any analytical value.  For that matter, it would have no relevance to whether the occurrence was unfounded or unnaturally occurring either.  Hence, there is no need to include an unobserved evidence type.

ACH software was developed by Palo Alto Research Center (PARC) in collaboration with Richards J. Heuer, Jr. . PARC is making the presently downloadable version of the program available to the general public at no cost when used for non-commercial or educational purposes subject to the terms and conditions of its end user license.[4]

The software may be downloaded free of charge at:

This software can easily be used to identify and question assumptions that are influencing your thought processes in your investigation or research. ACH software comes with a detailed tutorial that explains the methodology and procedures.

In the realm of paranormal investigation, the ACH software is an interesting way to record each piece of evidence and weigh it against each hypothesis before reaching a conclusion. I recommend that the paranormal investigator/researcher consider evaluation of ACH software with a view to assisting in maintaining a record of methodology and how evidence was weighed against hypotheses.

[1] Analysis of Competing Hypotheses, by Richards Heuer Jr.

Central Intelligence Agency Web Site:

[2] Ibid

[3] Ibid

[4] ACH Software Download Page ,

Copyright 2006 Palo Alto Research Center Incorporated,

3333 Coyote Hill Road

Palo Alto, CA 94304 USA  ACH2.0.5