by Judith Curry , June 28, 2019 in WUWT

Some reflections, stimulated by yesterday’s Congressional Hearing, on the different strategies of presenting Congressional testimony.

Yesterday’s Hearing provided an ‘interesting’ contrast in approaches to presenting testimony, when comparing my testimony with Michael Mann’s.

What are the purposes of expert testimony?

There is an interesting document entitled A Guide to Expert Testimony for Climate Scientists, funded by the US National Science Foundation.  Most of this is related to court room hearings, but some is relevant for Congressional Hearings.  Excerpts:

 

Experts may do one or more of the following:

• Provide the decision-maker with factual information and background to provide the decision-maker with an adequate context for the decision.
• Apply expert knowledge to the facts of a case and render an opinion about the facts, such as whether certain conditions actually caused an effect.
• Explain scientific principles and theories to the decision-maker.
• Extrapolate from the actual facts or hypothetical facts and rendering an opinion regarding the likelihood of an event or occurrence. Experts may speculate on events or occurrences because of their special knowledge or training.
• Provide an opinion that contradicts or undermines the opinions or conclusions of an expert who testified for the opposing party.

If you are assigned to cross-examine an expert, you should prepare questions that test and challenge the witness on the following subjects :

• Lack of thoroughness in investigating the facts or data;

• Insufficient testing of the facts or data;

• Lack of validity and reliability in testing of facts or data;

• Existence of other causes or explanations for conclusions or outcomes;

• Show differences of opinion among experts

…