Unified Motive Scales (UMS)
Summary: The UMS are the result of a joint analysis of 14 existing and 7 new motive scales for achievement, power, affiliation, and intimacy. Based on item response theory, they provide higher measurement precision in a wider range of the traits with fewer items than existing questionnaires.

Several different self-report measures of motivation exist. Although frequently used, only few studies ever tried to compare these different measures with regard to their psychometric properties. This lack called for a systematic analysis of these inventories based on a modern statistical approach. Thus, an item response theory analysis of the central motives (Achievement, Afifliation/ Intimacy, and Power) has been carried out.
Therefore, in three studies 21 different scales for these motives have been administered to 1500+ participants, containing the three subscales Achievement, Dominance (Power), and Affiliation of the Personality Research Form (PRF; Jackson, 1984), the Personality Values Questionnaire (PVQ; McClelland, 1991), the Achievement Motive Scale (Lang & Fries, 2006), the Mehrabian Affiliation Tendency Questionnaire (MAFF; Mehrabian, 1970), the Mehrabian Sensitivity to Rejection Questionnaire (MSR; Mehrabian, 1994), the Goals Questionnaire (Poehlmann & Brunstein, 1997), and additional self-constructed items (Schönbrodt & Dislich, 2010). The Samejima (1969) graded response model was used to test whether the existing self-report measures of motivation suffer from scaling problems and to construct new optimized scales based on the complete item pool.
Results show that commonly used motivation scales can be improved in a number of important ways; thus, new unifying motive scales are presented that map on the underlying theoretical dimensions, are unbiased in respect to gender, and are able to provide a higher precision with fewer items. A fourth study showed that the improved psychometric properties also are reflected in an incremental validity of the UMS in comparison to existing questionnaires.
Short scales (6 or 3 items per scale) are provided for use in round robin designs.
More information
The publication, data sets, the items, and additional informations can be obtained from http://www.nicebread.de/research/quest/UMS.