The respondent is asked to indicate a preference between two equally popular interests rather than simply like or dislike. While a like-dislike format has the appeal of simplicity, accumulating research has indicated that this type of format is prone to systematic bias.
Perhaps the most unique feature of the JVIS is its method of scale construction. Each scale was designed to measure the interest designated by the scale name and to be relatively unrelated to other scales. To accomplish this result, careful attention was paid to the preparation of a large pool of activities. The ultimate quality and validity of a vocational interest survey rests on the fidelity to which its constituent activities reflect the interest or interests in question. In the case of the JVIS, extraordinary measures were introduced to foster careful item development and selection. This was followed by administration of these items to large samples of males and females, well over a thousand of each. Final activity selection involved a series of multivariate psychometrically-based procedures designed to select activities most clearly related to the interests being assessed, to suppress response biases, and to minimize the redundancy between scales. From the initial activity pool of well over 3,000 items, the very best have been retained for use in the published JVIS.
Another feature of the JVIS is that it places equal emphasis upon the measurement of interests of women and men. The Survey was standardized in such a way that an equal number of males and females contributed to the selection of activities and scales, and that activities were required to show discrimination for each sex separately. The format allows males and females to be measured in terms of a common set of interest dimensions which do not make discriminations on the basis of traditional male and female occupations.