The coach-rating scale for Achievement-Motivated Behavior in Individual Sports (AMBIS-I) was constructed to measure achievement motivation, not from athletes’ own views but from coaches’ perspectives. The tool was already checked for reliability as well as content, factorial, and concurrent criterion validity (Zuber and Conzelmann, 2019). To further establish construct and criterion validity, two different samples were involved. Sample 1 included 67 experienced coaches rating their 278 athletes on the three AMBIS-I dimensions proactivity, ambition and commitment. In sample 2, 157 athletes completed self-report questionnaires measuring motivational and volitional concepts. Congruent and discriminant construct validity were assessed using the QCV-procedure (Westen and Rosenthal, 2003) by comparing experts’ predicted and empirically observed correlations between the coaches’ ratings on the AMBIS-I with the self-ratings of validated instruments. Consistent with theoretical expectations, achievement goal orientations, self-determination and self-optimization show significant positive relationships to the AMBIS-I scales, the negatively formulated volitional concepts, negative ones. As indicated by the 0.87 ≤ r_alerting-CV ≤ 0.95, the general patterns of the expert’s predictions triangulate consistently with the observed correlations. The findings concerning absolute agreement were mixed. Even though the ICCs suggest sufficient to good consistency, the values of r_contrast-CV are considerably lower. To indicate criterion validity, AMBIS-I display medium to large correlations with the actual performance level estimated by the coaches and small to medium correlations with the assigned potential for subsequent success one year later. In summary, we found solid indications, that AMBIS-I is a valid measure of achievement-motivated behavior in individual sports from coaches’ perspective.