Described the development of a Carelessness Scale for the MMPI, which can be used to detect whether the client or patient is willing or able to complete the MMPI in an appropriate manner. The Carelessness Scale in conjunction with the T R Index correctly classified 92y0 of the 150 profiles that were examined in this study as valid or invalid.The clinician who is interpreting the MMPI frequently is faced with the problem of determining the acceptability of an MMPI profile that appears invalid or a t least of questionable validity according to the traditional validity indicators (i.e., Scales L, F, and K). The T R index, the number of inconsistent responses to the 16 items of identical content that are repeated in the group form of the MMPI, has been suggested as an additional means to determine the acceptability of a profile. Beuchley and Ball (1952) reported that this index was helpful in distinguishing between vagaries in responding and consistency in responding for profiles with moderately high or higher F Scale scores. More recently, Greene (Note 1) and Jones, Neuringer, and Patterson (1976) have provided additional support for the use of the T R index in determining the validity of a MMPI profile. For example, Greene found that the T R Index was particularly helpful in identifying profiles of questionable validity that were not detected by the traditional validity indicators.Haertzen and Hill (1963) developed a carelessness scale for the Addiction Research Center Inventory that included both identical items that are repeated and items that are psychological opposites. Their work indicated that psychologically opposite items were more sensitive than the repeated items in detecting the inability or unwillingness of the person to complete their inventory appropriately. Dahlstrom, Welsh, and Dahlstrom (1972) concluded that items made up of psychological opposites would be a valuable adjunct to the T R index. The present study consists of the development of such a scale for the MMPI, which can be used in conjunction with the T R index to determine the validity of an MMPI profile.
METHODOne hundred and fifty individuals used in this study were divided equally among three different populations : patients a t a large Veterans Administration Hospital, clients a t a University Psychology Clinic, and college students enrolled in introductory psychology. The former two groups completed the RlMPI as part of their routine intake evaluation, while the latter group was administered the RilMPI specifically for this study.
RESULTSEach individual's responses to the 566 items on the MRIPI were keypunched and became the data to be analyzed. The data for each of the three groups of individuals next were placed in a 566 x 566 matrix, and a computer program selected all possible nonredundant pairs of items that were answered in a consistent direction more than 90% of the time. That is, a pair of items was selected if 46 out of the 50 individuals within a group answered the first item of the pair either true or false and the othe...