Self Determination Theory (Deci & Ryan, 1985a) describes diverse types of motivation, situated throughout a theoretical continuum which comprises a decrease in the regulation of behaviors, from highest to lowest. These are intrinsic motivation, identified regulation, introjected regulation, external regulation, and amotivation. These types, their influential factors, mediators and outcomes, integrate a hierarchic model which entails three levels: global, contextual, and situational (Vallerand, 1997). This paper presents the design and analysis of psychometric features of the Academic Motivation Scale-Situational (AMS-S) aimed at the assessment of motivation towards specific academic activities under specific circumstances. It was developed on the grounds of the Self Determination Theory's hypotheses as well as the Hierarchic Model of Intrinsic and Extrinsic Motivation (HMIEM) posed by Vallerand (1997). The sample was composed of 364 colleges students (62.6 % females, 37.4 % males) between 18 and 35 years old (M = 22.97, SD = 3.00) with different majors at the University of Buenos Aires (Argentine). Items were written up to represent each type of motivation formulated in the model, according to the question which must be borne in mind while responding to the scale: "Why are you at the faculty right now?" The original pool of items was evaluated by five experts in order to analyze content validity evidences. A further pilot study was performed with a small group of students, aiming at the exam of face validity evidences. The preliminary version of 44 items obtained up to then was analyzed on a standardization sample. Polychoric covariance matrices were employed once the univariate normality hypothesis was not verified for the items. The ordinal nature of data demanded such a treatment as well. The statistical package FACTOR (Lorenzo-Siva & Ferrando, 2013) was used to develop an exploratory factor analysis with minimum rank factor analysis (MRFA) extraction method followed by direct Oblimin rotation (KMO = .887; Bartlett's Sphericity Test: chi(2) = 4525.6 (df = 351; p < .01). A 3-factor model which explained 68.01 % of the common variance was isolated retaining 27 items (F1 explained 18.1 %, F2, 23.2 %, and F3, 26.8 %). Regarding the items content, the extracted factors were labeled as extrinsic motivation (F1), amotivation (F2), and intrinsic motivation (F3). Additionally, internal consistency of the scales was estimated by means of ordinal alphas, with adequate coefficients in all cases (F1 = .84, F2 = .95, and F3 = .94). In order to test the self-determination continuum hypothesis entailed in the model, each dimension of the scale was correlated with the rest of them. Significant and positive associations (p < .05) were found between the adjacent scales, and negative between the non-adjacent ones, thus endorsing theoretical statements. Correlations between the scales' scores and the similar ones of Academic Motivation Scale (Academic Motivation Scale-EMA in Spanish-Stover et al., 2012; Vallerand et al., 1989) were calculated to analyze convergent validity evidences. Significant though weak statistical associations (p < .05) were found when comparing equivalent and opposite motivational types in both tests. Finally, statistical norms to be employed with local college population were calculated. Summarizing, up to the moment the scale has achieved adequate results in terms of preliminary validity evidences and reliability, supporting its appropriate psychometric quality to be used with local college students. The main weaknesses of the study rely in the sample size, which restricts wider generalizations, as well as the lack of semi-confirmatory factor analyses and psychometric studies on stability of measures, which must be developed in further steps. The analysis of the link between situational, contextual and global measures of motivation is also strongly suggested, taking into account the reciprocal effects among them.
