Science and 'Consistent with' Evidence

• Author: Alan D. Gold
• Pages: 223-232

[223]

Chapter 8

Science and “Consistent with”

Evidence

    expert evidence is sometimes befuddled by what has become a

favourite phrase of prosecution experts, especially in sex abuse cases: “consistent

with.” ere are two ways in which this misleading phrase does harm. In the

context of identication and comparison issues, the phrase accurately means an

absence of dierence but is erroneously taken to mean a presence of identity. In

the dierent context of cause and eect or event and sequelae, the phrase is used

to hide logically worthless tautologies or unfavourable and damaging remote

probabilities. Essentially, some factor that might otherwise appear damaging to

the prosecution is explained away by the expert with that turn of phrase.

Regarding identication issues, it has already been noted that the concept

of “consistent with” came in for criticism for its use in the context of bre and

hair evidence adduced at one of the trials of Guy Paul Morin. One of the rel-

evant conclusions of that inquiry was that “[c]ertain terms, such as ‘match’ a nd

‘consistent with’ were used unevenly in the criminal proceedings and were pot-

entially misleading. e use of these terms contributed to misunderstanding of

the forensic ndings and their limitations.”

One of the expert witnesses who testied before that inquiry elaborated on

the problems involved in this terminology in testimony he gave in a criminal

e Honourable Fred Kaufma n, Commissioner, Report of the K aufman Commission on

Proceedings Inol ing Guy Paul Morin (Toronto: Ministry of the Attor ney General, ),

online: w ww.attorneygeneral .jus.gov.on.ca/english/about/pubs/morin at –. e

term “match” was also there de constructed.