It is important to bear in mind that the Higher Judicial Services require the selection of judicial officers of mature personality and requisite professional experience. In service judicial officers are expected to have a greater familiarity with the law and the procedure based on their experience as judicial officers. While an objective written examination can be the best gauge of the legal knowledge of a candidate, the viva voce offers the best mode of assessing the overall personality of a candidate

In Lila Dhar v. State of Rajasthan,17 this Court noted the importance of
giving necessary weightage to the interview test in the following words:
“6. Thus, the written examination assesses the man’s intellect and the interview test the man himself and “the twain shall meet” for a proper selection. If both written examination and interview test are to be essential features of proper selection, the question may arise as to the weight to be attached respectively to them. In the case of admission to a college, for instance, where the candidate’s personality is yet to develop and it is too early to identify the personal qualities for which greater importance may have to be attached in later life, greater weight has per force to be given to performance in the written examination. The importance to be attached to the interview-test must be minimal. That was what was decided by this Court
in Periakaruppan v. State of Tamil Nadu [(1971) 1 SCC 38 : (1971) 2 SCR 430] , Ajay Hasia v. Khalid Mujib Sehravardi [(1981) 1 SCC 722; 1981 SCC (L&S) 258 :
AIR 1981 SC 487] and other cases. On the other hand, in the case of services to which recruitment has necessarily to be made from persons of mature personality, interview test may be the only way, subject to basic and essential academic and professional requirements being satisfied. To subject such persons to a written examination may
yield unfruitful and negative results, apart from its being an act of cruelty to those persons. There are, of course, many services to which recruitment is made
from younger candidates whose personalities are on the threshold of development and who show signs of great promise, and the discerning may in an interview test, catch a glimpse of the future personality. In the  case of such services, where sound selection must combine academic ability with personality promise, some weight has to be given, though not much too great a weight, to the interview-test. There cannot be any rule
of thumb regarding the precise weight to be given. It must vary from service to service according to the requirements of the service, the minimum qualifications
prescribed, the age group from which the selection is to be made, the body to which the task of holding the interview-test is proposed to be entrusted and a host of
other factors. It is a matter for determination by experts. It is a matter for research. It is not for courts to pronounce upon it unless exaggerated weight has been given with proven or obvious oblique motives. The Kothari Committee also suggested that in view of the obvious importance of the subject, it may be examined  in detail by the Research Unit of the Union Public Service Commission.”