1. Exploratory Factor Analysis of the Portuguese
Zimbardo Time Perspective Inventory – ZTPI
Victor E. C. Ortuño1 & Vítor Gamboa2
1Faculty of Psychology and Educational Sciences, University of Coimbra –
2Faculty of Human and Social Sciences, University of Algarve –
Time perspective (TP) is the non-conscious psychological process by which individuals encode, store and retrieve information about personal and social objects and events, through the use of temporal categories (Zimbardo & Boyd, 1999). Thus, TP is strongly related to the cognitive and behavioral mode of operation of each individual. Concerning the measures of time perspective, the Zimbardo Time Perspective Inventory - ZTPI (Zimbardo & Boyd, 1999) has been presented as a reliable measure. The aim of this study is to present a Exploratory Factor Analysis of the ZTPI and to discuss his results of internal consistency. The sample is formed by 436 Portuguese subjects ( % are female and % are males) with an age mean of 24.4 years (SD = 8.4). The exploratory factor analysis (Varimax rotation) of the Portuguese version of ZTPI revealed 5 factors, which explained 35.30% of the total variance. This results are compared with the original ZTPI (Zimbardo & Boyd, 1999) and others international versions.
Sample: It consists of 436 subjects of which 299 (71.4%) are female and 120 (28.6%) are male. Ages are between 16 and 63 years old (M = 24.4, SD = 8.4). 304 (69.7%) of the participants are college students, 58 (13.3%) are high school students, the remaining 74 (17%) participants develop activities related to the secretariat and public attendance.
Instruments: It was used a sociodemographic questionnaire, aiming to characterize the sample, and also the Zimbardo Time Perspective Inventory - ZTPI (Zimbardo & Boyd, 1999) in its Portuguese version (Ortuño & Gamboa, 2009), which consists of 56 items ( 5-point Likert scale) that are grouped into five subscales: Past Positive, Past Negative, Present Hedonist, Present and Future Fatalist.
The results obtained by the Portuguese ZTPI are very positive because we could verify that the factorial structure of five factors is similar to the original ZTPI; most items saturated> .30 on their respective factors and through the analysis of the Scree Plot the five factors were also found. In terms of internal consistency of the factors the results were also very acceptable. Thus it is concluded that the Portuguese ZTPI presents strong affinities of both structural and internal consistency with the original ZTPI as with other versions developed in other countries such as France (Apostolidis & Fieulaine, 2004), Spain (Diaz-Morales, 2006), Brazil (Milfont, Andrade, Belo & Persona, 2008), Russia (Sircova, Mitina & Sokolova, 2008) and Lithuania (Liniauskaite & Kairys, 2009) among others, so this is an instrument with strong potential for cross-cultural studies of temporal perspective.
Method
Conclusions
Exploratory Factor Analysis: Trough the analysis of the major components (with Varimax rotation and missing values replaced by the mean) and the analysis of the Scree Plot were extracted five factors (Table 1) whose composition seems to be the same factors found by Zimbardo & Boyd (1999 ) ZTPI the original. The total variance explained by the inventory is of 34.44% and the KMO value of sampling adequacy is Of the 56 items composing ZTPI, 47 have loadings > .30 on their respective subscales, an amount that is recommended by Kline (2000) for factorial analysis. The variance explained by each factor were: Past Negative = 8.25%, Present Hedonist = 7.72%, Present Fatalist = 6.86%, Future = 6.44% and Past Positive = 5.18%.
Cronbach´s Alpha: The presented alpha values are very good, and range between .633 and .794 (Table 1), these are quite near to those obtained by Zimbardo & Boyd (1999) in the original instrument as well as other international versions. Only the removal of item No. 41 significantly improves the Cronbach alpha in its respective factor (Past Positive).
Results
References
Apostolidis, T. & Fieulaine, N. (2004). Validation française de l´échelle de temporalité The Zimbardo Time Perspective Inventory (ZTPI). Revue européenne de psychologie appliquée, 54,
Diaz-Morales, J.F. (2006). Estructura factorial y fiabilidad del Inventario de Perspectiva Temporal de Zimbardo. Psicothema, 18,
Kline, P. (2000). A psychometrics primer. London: Free Association Books.
Liniauskaite, A. & Kairys, A. (2009). The Lithuaniam version of the Zimbardo Time Perspective Inventory (ZTPI). Psichologija, 40,
Milfont, T. L., Andrade, T. L., Belo, R. P., & Pessoa, V. S. (2008). Testing Zimbardo time perspective inventory in a Brazilian sample. Interamerican Journal of Psychology, 42,
Ortuño, V. & Gamboa, V. (2009). Estrutura factorial do Zimbardo Time Perspective Inventory – ZTPI numa amostra de estudantes universitários portugueses. Avances en Psicología Latinoamericana, 27(1),
Sircova A., Sokolova E.T. & Mitina O.V. (2008) Адаптация опросника по временной перспективе Ф. Зимбардо на русскоязычной выборке [Adaptation of Zimbardo Time Perspective Inventory]. Psikhologigesky Journal, 3,
Zimbardo, P.G. & Boyd, J.N. (1999). Putting time in perspective: a valid, reliable, individual-differences metric. Journal of Personality and Social Psychology, 77(6),