I expect "expert judgement" in science/engineering to be based on knowledge - and nothing else. I expect "true experts" to even disclose where a question may exceed their area of knowledge.

So: where exactly do you see a difference?

Thank you U. Dreher

I agree an "expert judgement" can only be made by "an expert".  

Furthermore, an expert is somebody who has both knowledge and experience in the specific science/engineering topic on which the judgement is being made.   

Of course a "good" expert knows their limitations and keeps their judgements within their area of knowledge and experience.  

So: where exactly is the difference? (to re-purpose your question).  

In truth that is the point of my question, to get a general agreement from RG community on "what exactly is an expert judgement".   

In my opinion; an "expert judgement" can only be made by a "true expert" and that to be a true expert requires knowledge and experience in the specific science/engineering topic.  

This does raise problems like how are "true experts" to be recognised and I can only offer the opinion that only one's peers can ever "recognise a true expert".  Is there any other way?  

Finally; we should remember the quote:

“An expert is one who knows more and more about less and less until he knows absolutely everything about nothing.”

― Nicholas Murray Butler

As you have already said...expert judgement can only be made by true expert and he/she requires knowledge + experience....

In my opinion also, decision bound by knowledge is a subset of expert judgement...because there is a fair probability that an expert will take a better decision (than any other) with any available information.

How to recognize a true expert is a difficult question to answer...Although it is not a direct answer but still : if I am in a condition when I need some help/suggestion for some decision making inside my organization...the person whom I approach for discussion is the best possible expert available for me...its a natural selection, I dont need to make effort to it, it happens....may be because I know them well and their capability also...so I also feel peers and practitioners in a field could recognize the true expert (under a true condition)

Regards

To tell "real experts" from "so-called experts", you need at least basic knowledge in the respective area. Which may be challenging. According to my personal experience, it is often quite easy to distinguish the ones from the others :)

Regards

One of the best ways of learning while doing research is to consult with an expert.  Therefore, when we come up against a problem that is outside of our own knowledge and experience we seek advice from an expert; somebody who has more knowledge and  experience than us in that topic.  If this person is known to us and working in the same organisation then this makes the process all the easier (or perhaps we use RG).  From the answers of Naveen and U. Dreher I would suggest that we all feel able personally to recognise a "real/true expert"  when we consult one.  

However, what happens when you get a judgement that you don't like?  Do you then go as ask for a "second opinion"?  

Or to put the shoe on the other foot; what happens if you are the expert, you give what you think is a good judgement but the recipient does not like the answer.  Perhaps the experiment you suggest is too costly or too time consuming or the calculation is beyond that person, or they don't know how to code that algorithm?  

Perhaps that person goes and asks for a second opinion and gets a different judgement an easier, simpler answer to their question.  How would the recipient know which expert was giving the correct judgement?  

I've done a lot of consulting: Usually starting when some project had already gone bust more than once.

In my field (electrical engineering), sometimes multiple valid solutions exist. So opinions differing from mine aren't rare. And the advice depends on the completeness of the informations available to me. It is not rare that important facts are missing. Thus everybody is free to seek a second opinion or to reject my advice. If it works out, I may learn some new things. If it doesn't work out, I'm the wrong person to complain about the "bad fate" :)

Whether I dislike some advice doesn't matter: mathematics, physics, chemistry etc. are not about liking - they are factual science where at some point right/wrong can be measured :) The same should be valid for my "customers". If they don't like my advice: ok. If this results in a loss of time and money: this is neither my time nor my money :)

On the other hand: I know a lot, but not all and everything.

Or - as I once worded it: "I'm not god."

Dear Ulrich

Thank you for your contribution and please know that I fully agree with you.  

However, this gets me thinking about differences between scientific/engineering disciplines.    For example there is a question I came across on RG from Barry Turner "Why is paleoanthropology the most contentious of sciences?"

I am sure Barry was just having a bit of fun asking this question.  Nevertheless, the answers throw up an interesting conundrum.  The most popular answer from Peter J Richerson "The amount of rancor in scientific fields seems correlate with the difficulty of disproving hypotheses. "

I guess in your field (electrical engineering) and many other fields our technical advice and judgements are based on known facts and can be quickly tested and we learn about the outcome quickly too.    Paleoanthropology is an extreme case where the facts are few and far between and hypotheses are difficult to test.  

My own area of research is perhaps somewhere in between; I study and try to understand the outcome of experiments so that I can derive models that can be used to predict the future.  Unfortunately, the experiments are expensive and time consuming and not often reproduced by other researchers.  The real test of the models, i.e. comparison with the real world takes 10s of years and the outcomes of the real world experience is rarely studied in enough detail to actually validate the models and their predictions.  It is often Joked in my field that there are more models/theories than researchers!  

Therefore, in my case judgement is a bit more contentious than in other fields, which explains why I thought to ask this question.  

https://www.researchgate.net/post/Why_is_paleoanthropology_the_most_contentious_of_sciences

I admit that right/wrong is easier to decide in the "exact" disciplines. Though multiple may exist - resulting in different equivalent solutions to a "problem". But even in these fields, a lot of decisions are not based on "known facts" but on derivations from more or less similar problems solved in the past. Admitted: usually possible solutions are easily evaluated. At least if you master what I call "orthogonal testing": setting up tests such that the influence of a single attribute becomes measurable.

Regarding the "not-so-exact" sciences, I expect decisions to be based primarily on experience. Though "knowledge" may apply as well.

Whether the rancor comes from the difficulty of disproving hypotheses or from the difficulty of proving them: both arguments apply. Usually leading to something easily attributed as "wars of belief". Whether in paleoanthropology, in psychology or alike... When it comes to processes on the atomar/molecular level, even physics and chemistry bear significant conflict potential.

If you like another joke: "10 physicists (chemists) - 20 opinions."

'Expert Judgement' in an academic forum such as this is quite different  from a 'Technical Expert' as often defined by Industry, where the expectatiosn are closer to 'absolute certainty via  peer review & peers obtaining repeatedly the same results' - Hence the Expert opinion is rarely obtained early in a development cycle nor quickly or cheaply

If you are looking in Industry- the technical expert usually arrives in the position based upon experiance & trast of the  other less technical management, they look to give advice to collegues based on past experience either directly or indirectly pertinent, on a topic that (s)he cannot ask others to duplicate & validate. Often it is to give the company a technical advantage over competitors - eg under time constraints.

Hence with internal testing possible as a baseline, an 'Expert' in industry will give what is often refered to as an 'Engineering Guesstimate' on how to move forward into an unknown or uncertain area of applied science . Based on gut feeling  which has been inspired by past experience, re-assured by internal testing as time permits & possibly boyed up by talking obliquely to peers (so as not to give the advantage to them)

I like the way the question is posed and often the differeniator is 'Time to market'; where academic's often have a much longer time frame available than industrial engineers. These engineers know that peers in competitor companies will be equally inspired by the same things as them to develop the product quickly and so have to give a best Engineering opinion based on the data available :  experience usually take them closer to right answer than others first time.

 An Engineer risking trying to share on an Academic forum. 

Expert judgement is a valuable source of information in risk management. Especially, risk based decision making relies significantly on quantitative risk assessment, which requires numerical data describing the initiator event frequencies and conditional probabilities in the risk model. This data is seldom found in databases and has to be elicited from qualified experts.

The Rasmussen Report (WASH 14000) was the first study using extensively expert judgements to assess accident risks in commercial nuclear power plants.

Dear Timothy

Thank you very much for you contribution, I very much value your point of view.  In particular, when I asked the question I had in mind to establish the principal that only an 'Technical Expert' can actually make an 'Expert Judgement'.  Even then this is limited to, only in their personal  area of expertise.  

Do you agree with this and how can other people recognise when the judgement has been made by a ' Technical Expert'?  

Dear Florian

I should study the Rasmussen Report (WASH 14000) I suspect I will learn much.  

How reliable would you say that expert judgement was?  What would we do to increase the reliability of 'expert judgement'?

http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/10/482/10482214.pdf