The importance of objectivity in engineering, and a case study.
The public, clients and employers expect that an opinion given by a professional engineer will be as objective as they are able to make it. This means that it will not be biased or improperly influenced.
In practice, it can be difficult to establish whether a given opinion is truly objective or not. For example, say you are asked for your opinion on whether your employer should invest in a particular type of software, from a manufacturer whom you personally dislike. This may be fine if your dislike is based on previous bad experiences of using their software.
However, if it is based on, say, the fact that a family member used to work for the software manufacturer and felt that he or she was badly treated by them, you should clearly not allow this to influence your opinion.
As a general rule, if you are happy to give an honest account of all the factors that influence your opinion, then that opinion is probably objective.
You may have an ethical duty not to put yourself in certain situations which may threaten your objectivity. For example, one reason engineers and other professionals are not allowed to take bribes and inducements is because this is likely to damage their ability to be objective.