Digital ForensicsDr. Randy M. Kaplan

Drexel University

Testimony

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The Salient Questions of Testimony

Is the testimony relevant?

Is the witness believable?

Do other similarly qualified witnesses agree with these conclusions?

Is the witnesses testimony comprehensible?

Is there admissible evidence to show that the testimony is factual?

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Roles of An Expert Witness

Consulting Expert

Court’s Expert

Testifying Expert

Expert as a Witness to Fact

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Consulting Expert

Consulting experts provides a combination of

training

review of existing technology

advice on strategy

assessment of the competitions expert

strategy going into court

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Court’s Expert

Similar to the consulting expert

A court appointed or stipulated expert

Serves in the consultant capacity but performs his or her technical consulting for the court itself

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Court’s Expert

Valuable when judges preside over major cases where

both sides have their experts

expert view are wildly divergent

situation is more common then might be imagined

especially true in cases involving nascent technologies

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Court’s Expert

This type of expert is independent

Understands arguments posed by both sides

Explains strengths and weaknesses of both arguments

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Testifying Expert

The one that most technologists think of first when the topic of serving as an expert witness comes up

Raw functions may be similar to those of a consulting expert

Constraints are considerably different

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Testifying Expert

Implicit ethical responsibility

to be scrupulous

to be objective

No presumption of privilege that applies to the communications between the attorney and the testifying expert

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Testifying Expert

Any communication, electronic pr physical, is probably not confidential and subject to discovery

Typically work patterns need to be altered in order to deal with this particular issue

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Expert as a Witness to Fact

Expert will be asked to testify as a normal, non-expert witness

Expert is only expected to testify to events he or she personally experienced, actions he or she took, or things he or she said

The expert’s technical mastery is not the central feature of the testimony

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Expert as a Witness to Fact

The fact that the witness is also an expert in one or more areas is also bound to bias the fact finder’s judgement

This may effect the perception of the credibility and demeanor of the witness