Self-leadership has often been subject to criticism that it is not sufficiently differentiated from other concepts. The theory is repeatedly compared to self-management and self-regulation (Godwin, Neck & Houghton, 1999). Another source of critique derives from the fact that, to date, most self-leadership research has been conceptual in nature (Andressen et al., 2012). As such, only a limited number of research instruments has yet been applied to empirical investigations. All previously used measures are grounded on a prototype developed by Charles Manz and Henry Sims (1987, 1991). In English and German literature, the scale most frequently used today is the Revised Self-Leadership Questionnaire by Houghton and Neck (2002). Showing potential for bias, the RSLQ still lacks satisfactory reliability (Furtner, 2012; Furtner & Rauthmann, 2011; Konradt et al., 2009). Furtner and Baldegger (2013) hence recommended the development of an enhanced instrument. The effort has since been undertaken by Furtner and Rauthmann (in prep.) who developed the Self-Leadership Skills Inventory. The measure produced satisfactory reliability in a first academic application, yet it has not been previously deployed in organizational context up to this point. Applying the measure for the first time, the factor analysis for the SLSI suggests excluding the first-order factor of self-reminding as two items produced considerably lower factor loadings than others. Reliability of selfreminding also reported a smaller value compared to other first-order factors, yet of good quality (a = .82). An expert panel tested the SLSI further for content validity. Skepticism was predominantly targeted at the fact that items were perceived to be too similar-sounding or lacking proper differentiation. Items of the SLSI were clustered to three statements, each belonging to different constructs. As tests of item order are not available yet for the measure, a different order could have changed perceptions of followers. A last point of consideration is the assessment method of self-ratings done by followers. Self-ratings are criticized for causing potential bias based on social desirability (Podsakoff, MacKenzie, Lee & Podsakoff, 2003, p. 881). Crowne and Marlow (1964) define social desirability as referring “to the need for social approval and acceptance and the belief that it can be attained by means of culturally acceptable and appropriate behaviors” (p. 109). Yet, reflecting a cognitive construct, other-ratings would be just as subjective.