Participants were 357 undergraduate college students at a Spanish university. These students were enrolled in a bachelor's degree course in early childhood education, or in primary education. Students were approached in their classroom. Two hundred ninety-one students (81.5%) completed questionnaires. The mean age of the university sample was 23 years (SD=4.9, range 18–43 yrs.). There were 88.3% women and 11.7% men in the sample. The percentage of women studying early childhood education or primary education is 87.5% at the University of Barcelona; there are no significant differences with our sample (t=1.455 and p=.147). With regard to the grade, there were 56.7% (n=165) students of Early Childhood Education and 42.6% (n=124) were students of Primary Education, the 0.7% (n=2) did not provide their Bachelor's degree. The large majority was born in Spain (95.2%), 1.4% being Central American, South-American (0.7%), and African (0.3%); 2.4% of the respondents did not provide their country of birth (see Table 1).

Based on Hollingshead four factor index (Hollingshead, 1975), the participants’ families corresponded to the following categories: 13.7% low Familiar Socioeconomic-Status (FSS), 17.5% FSS low-medium, 18.6% FSS medium, 33.3% FSS medium-high, 12.7% FSS high, and the 4.1% did not provide information.

The following questionnaires were administered:

The socio-demographic data sheet. It provided information about several characteristics of the group: age, gender, year of study, degree being studied, country of birth, and parental educational level and occupational field. These last two factors were introduced in the Hollingshead Occupational Scale (Hollingshead, 1975) to obtain family socioeconomic status. The students specified their high school grade-point average and the number of academic credits they had successfully completed. This last variable was considered as an indicator of academic progress.

The Revised Life Orientation Test – LOT-R (Scheier et al., 1994) in its Spanish version (Otero, Luengo, Romero, Gómez-Fraguela, & Castro, 1998). The LOT-R consists of Optimism and Pessimism scales, with 10 items (three items assess optimism, three assess pessimism, and four of them are fillers). The respondents indicated the extent to which they agreed with each item on a 5-point Likert scale that ranged from strongly agree to strongly disagree. The internal consistency (Cronbach's alpha) ranged between .74 and .78 (Schou, Ekeberg, Ruland, Sandwik, & Karesen, 2004).

Brief Symptom Inventory. The BSI-18 (Derogatis, 2001) was used to measure participants’ psychological distress (PD). This inventory includes 18 symptoms to assess the degree of distress on a Likert-type five-point scale ranging from 1 (total absence of symptom) to 5 (full presence of symptom). The scale provides three groups of symptoms: somatization disorder, depression, and anxiety. A global severity index (GSI) and a positive symptom distress index (PSDI) were calculated. The test-retest reliability ranged from .78 to .90. Cronbach's alpha ranged from .81 to .90 (Derogatis, 2001). In the present research, Cronbach's alpha for BSI-18 were: somatization (α=.663), depression (α=.821) and anxiety (α=.736).

Ryff Scales of Psychological Well-Being. The scale PWB (Ryff, 1989) is a self-report scale designed to measure psychological well-being. The instrument consists of six subscales: Self-acceptance, Positive-relationships with others, Personal-growth, Purpose in life, Autonomy, and Environmental-mastery. Each subscale consists of 14 items divided approximately equally between positive and negative items. The self-acceptance dimension assesses positive attitudes held toward the self. The positive-relationships with others dimension assesses the ability to love, trust, and establish deep relationships with others. The personal growth dimension measures one's needs to actualize and realize one's potentials. The purpose in life item seeks to measure one's sense of directedness and goals. Autonomy assesses self-determination, independence, and an internal locus of control. Finally, the environmental mastery measures one's ability to manipulate and control complex environments. Participants respond on a 6-point Likert scale that ranges from strongly disagree (1) to strongly agree (6). Certain items are reverse coded. The total score is the sum of the 84 items. Ryff and Keyes (1995) reported the following internal consistency reliability coefficients ranged from .81 to .85. In the present research, Cronbach's alpha for PWB were: self-acceptance (α=.848), positive-relationships (α=.809), personal-growth (α=.778), purpose in life (α=.846), autonomy (α=.751), and environmental-mastery (α=.731).

This study was approved by Ethics Committee of the University of Barcelona (Spain) and was conducted in line with the guidelines of the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research (1978). Subsequent to a full explanation of the study procedures to students in their classrooms, students were invited to participate. A consent form to be signed by students was requested the day of the data collection. The participation of study was voluntary and anonymous. Students that declined to participate did not differ in age, socioeconomic status, or grade level from those who did participate.

The questionnaires were applied collectively in groups of 15–30 students over an 1-hour session in their classrooms. Students were informed that there were no good or bad answers, and that the answer should be chosen according to their own experiences. Special attention was paid in order to ensure privacy and confidentiality of the data, and to avoid random answers. Two members of the research team were present in the classroom to clarify doubts and help if necessary.

Descriptive analyses were conducted for each of the LOT-R items and their discriminatory power was calculated by item-total correlation which measures the relationship between a given item and the rest of the scale. For empirical evidence of the internal structure of the scale an exploratory factor analysis was conducted using the principal axis technique and Oblimin rotation. The Kaiser–Meyer–Olkin (KMO) measure of sampling adequacy was used to test whether the application was relevant to factor analysis. Two factorial solutions were confirmed: unidimensionality and bifactoriality. The loadings of the items to the factors were established at .30. The two-factor solution was accepted. Reliability analysis was conducted based on the analysis of internal consistency by calculating Cronbach's alpha. The minimum acceptable value for Cronbach's alpha coefficient is .60 and the expected maximum value is .90. No redundancy or duplication of items are thought to occur above this value. Criterion validity was examined using non-parametric Kendall's tau correlations between LOT-R and BSI (both total and scales scores) and PWB scales. Two analyses of linear regression were conducted to study the link between optimism and academic progress both in men and women. Control variables were age, socioeconomic status and the grade-point average in the student's academic transcript. The study used a stepwise selection method and Version 16.0 of the Statistical Package for the Social Sciences (SPSS) for the statistical analysis. For all the tests carried out, bilateral statistical significance was set at p equal to or less than .05.

Table 2 describes the means, standard deviations and response frequencies for the items in the LOT-R, as well as the item-total correlation and the estimation of the questionnaire's internal consistency. The absolute value of most of the correlations between the six items and the four filler items were found to be below .20. These results suggest that the filler items really operated as such, and these items were therefore not considered in subsequent analyses. The mean score for all the scale was 14.23 (SD=4.0, 2–23) excluding the filler items. The mean for the items assessing optimism was 7.46 (SD=2.6) and the mean for the items assessing pessimism was 5.22 (SD=2.1). The inter-item correlations matrix was analyzed using exploratory factor analysis. The estimation of internal consistency with Cronbach's alpha for LOT-R was .724.

To analyze the test's factorial structure in the target population we used the maximum likelihood method with direct Oblimin rotation. The Kaiser–Meyer–Olkin (KMO)=.752 and Bartlett's Test of Sphericity (χ2=393.372, p<.001) indicate the goodness-of-fit of the correlations matrix required for this analysis. The results of the factoring by PCA and Oblimin rotation are described in Table 3.

The factorial structure shows a bidimensional solution which explains 62.3% of the variance. The first factor, which explains 43.5% of the variance, gathers the items assessing optimism, with factor loadings between .689 and .874, and reaches α=.75.

The second dimension explains 18.8%, and gathers the items assessing pessimism, with saturations between .645 and .822, and α=.49. The correlation between the dimensions was highly significant (r=.46, p<.001).

Given the low number of items comprising each factor, reliability would be substantially increased if the number of items was doubled (Spearman–Brown prediction formula: α=.86 for Factor 1, and α=66 for Factor 2).

Table 4 describes the Kendall's tau correlations between the dimensions of the LOT-R and the global score of the scale with regard to the Brief Symptom Inventory (BSI) and the Psychological Well-Being (PWB) Scales. If we take into consideration two factors, optimism correlates negatively with the BSI, especially in Depression (r=−.460, p<.001) and Anxiety (r=−.401, p<.001) and correlates positively with the PWB Scales, especially in Self-acceptance (r=.620, p<.001), Environmental-mastery, (r=.589, p<.001), Purpose in life (r=.554, p<.001) and Personal-growth (r=.434, p<.001).

The pessimism factor (LOT-R) correlates positively with the BSI, especially in Depression (r=.358, p<.001) and Anxiety (r=.309, p<.001) and correlates negatively with the PWB Scales, especially in Self-acceptance (r=−.468, p<.001), Environmental-mastery (r=−.442, p<.001), and Purpose in life (r=−.389, p<.001).