Scientific Content Analysis (SCAN)

PVL is pleased to be able to offer a unique and sophisticated service – forensic language screening.

The creator of SCAN is a former lieutenant in the Israeli Police Department,  Avinoam Sapir.  While working as a Polygraph Examiner he noticed a correlation between polygraph results and various features of written statements.  From those observations he developed a technique for determining the veracity of a subject’s verbal or written communication.

Avinoam Sapir holds a BA in Psychology and Criminology from the University of Bar-Ilan and an MA in Criminology from the University of Tel-Aviv.  Since 1981 he has run his company,  the Laboratory for Scientific Interrogation from Phoenix,  Arizona.

Scientific Content Analysis (SCAN) is not a theory;  it is a technique for detecting deception and obtaining information by making a series of observations. It has been proved to be a scientifically based method which produces consistent results.

The basic premise is that the structure and content of a statement reveals whether the subject has made an attempt to deceive.  If a "lie" is something which is completely fabricated,  then few lie,  and perhaps 90% of what people say is truthful.  But many don't reveal everything.  Because they are reluctant to commit themselves to their actions, “…they hedge, feign forgetfulness, omit crucial facts and pretend ignorance.” 

However even though they may want to withhold information,  people’s words betray them.  They give away more information than they realise through their speech patterns,  and the structure and contents of their statements.  Every word a subject uses is important in determining the truthfulness of the information provided,  certain linguistic signals indicate that important information is missing,  and so by looking at the way in which language is used,  it is possible to detect meaning which would not otherwise be apparent.

Analysing a statement is a two stage process.  A truthful statement contains specific features.  Therefore the first stage is to determine whether these are present.  The second step is to determine the extent to which the statement differs from what would otherwise be a truthful statement.

A SCAN analyst is able to dissect a written or verbal statement and determine whether the author of the communication is telling “the truth, the whole truth and nothing but the truth”. 

To help you understand how SCAN is used to analyse statements we have included some of our case studies. We have analysed the public statements made by:

  • Taito Phillip Field, former Government Minister and the allegations of corruption made against him,
  • Graham Capill the former Christian Heritage Party leader convicted of sexually violating three young girls,
  • Ralph Gerdalan, former head of the NZ Problem Gambling Foundation; and
  • Mark Lundy the Palmerston North businessman convicted of murdering his wife and daughter.

For international examples of SCAN Statement Analysis, the FBI's Law Enforcement Bulletin is an excellent resource.

We are often asked to comment about the David Bain case. In domestic murder telephone calls to the Police, there is specific guidelines to follow that place the caller in one of two categories: Guilty Caller or Innocent Caller.  In this respect, a study by Dr. Susan Adams is of great value, especially when combined with the principles of SCAN. Dr. Adams' study is available on page 23 of the following FBI Bulletin: 
Is the caller the killer?