An expert is a specialist in the respective field and called as a witness in the court at that capacity. The qualities which possesses by expert witness are different from ordinary witness because generally witness can not give their opinion, but the expert generally make their opinion. Therefore, there are some important qualities of an expert witness as:
An expert must have expertise or specialization in subject he/she testifies in court.That is main reason of summoning him/her.The question of expertise may be decided upon the basis of an inquiry into academic achievements, professional training, experience in trade, means at the command and the application of those for coming to conclusion.
The language used by an expert must be simple, clear and comprehensive even to ordinary people.The subject should be able to present his/her evidence in clear words and if possible , through charts, photography, sketch and phomicrographs and make his/her opinion demonstrative so that same could be appreciated by a lay person.
An expert opinion must be relevant to both , the issue in question as well as to the established and recognized principles and findings of his/her subject. The findings must not be based on assumptions but on relevant data either from own experience or from the published works of accredited authors.
The court seeks for expert opinion in the presumption that such opinion will be more authoritative or more reliable due to his/her special knowledge on the subject. Another side of the basis of reliability is non –commitment of the expert to interests of either disputing party. They should not only be reliable but appear to be so, and that he/she should satisfy himself/herself against bias arising out of certain cases.