To further assess the validity and reliability of the TTPI, we used Study 2 to examine these issues in a clinical sample.
In addition we aimed to test the hypothesis that TTPI measures two components of time perspective--the bias to think about a transcendental future time and positive or negative attitude.
To test whether the TTPI measures awareness of transcendental future thoughts we used the Mindful Attention and Awareness Scale MAAS.
The TTPI was not significantly related with any of the TP subscales, the WHOFive Well-being Index, the Estonian Rosenberg Self-Esteem Scale, the MAAS and the DEPS Depression Scale.
The test-retest reliability of the Estonian version of the TTPI was assessed with 43 adult students and 11 psychotherapy clients over a 6-month period.
Two underlying dimensions of the TTPI, the MAAS mindfulness and well-being scales
With MDS we tested the hypothesis that the TTPI measures a time perspective--orientation towards a transcendental future time as well as an attitude (positive or negative), by making the data accessible to visual inspection and exploration in two-dimensional space.
Based on one dimension the TTPI measures a very different construct compared to mindfulness, or awareness of present thoughts and perceptions (Brown and Ryan 2003).
In our studies, we examined (a) the factorial structure of the Estonian TTPI, (b) the reliability (internal consistency and repeatability) and validity both in adult and clinical samples, (c) how the construct of transcendental future maps into the time perspective coordinates and (d) how the scale scores vary by demographic groups (age, sex, level of education).
However, this does not in itself demonstrate that the TTPI items are actually measuring a time perspective--the bias to think positive or negative thoughts about a transcendental future.
In the original TTPI (Boyd and Zimbardo 2008) the middle point of the scale is 'neutral'.
In the current research, the TTPI was related to the Past Positive perspective even more than in the original Boyd and Zimbardo (2006) study.