The core critical thinking skills, identified in "The Delphi Report" as essential elements for workplace and educational success, are targeted in a standardized 35 item multiple-choice assessment tool entitled the "Test of Everyday Reasoning (TER)" which is designed to provide a representation of a person's overall critical thinking ability. In this paper the reliability of the Greek version of the "Test of Everyday Reasoning (TER)" is investigated. In the research participated 350 Greek students. Reliability analysis was conducted for the overall sample of the research and the subgroups: (a) young students (11-13 years old) and university students, (b) male and female. Data showed that the Greek TER was a reliable instrument measuring critical thinking for the above mentioned groups.
In current educational research there is a widespread acceptance that critical thinking development is an important dimension of education (Coles & Robinson, 1989; Ennis, 1987; Garnett & Tobin, 1984; Krusse & Preseissen, 1987; McGuinness & Nisbet, 1991; Meadows, 1996; Paul et al., 1995; Perkins, 1993; European Union, 1995: 12; Gadzella et al., 2006). In Greece the "Cross Thematic Curriculum Framework for Compulsory Education" (1) and the new Curricula for elementary and secondary education state clearly that critical thinking is an important educational aim (Official Gazette, 2003).
In spite the fact that the necessity of developing student's critical thinking is proposed by academics, researchers and educators, there is great difficulty in defining it and, consequently, in assessing it. The concepts advanced by R. Ennis (1987), R. Paul et al. (1995), M. Lippman (1991), H. Siegal (1988) and R. Sternberg (1985a, 1985b, 1987) among others were prominent and influential. In the relevant literature critical thinking is conceptualized according to where emphasis is given each time: i.e. as logical fallacies (Dreyfus & Jungwirth, 1980; Jungwirth & Dreyfus, 1990; Jungwirth, 1987), as formal reasoning processes or skills (Blair & Johnson, 1980; Lawson, 1982, 1985; Obed, 1997), as scientific reasoning in general (Friedler et al., 1990) etc.
An historical benchmark in conceptualizing critical thinking is the consensus of a panel of 46 leading theoreticians, teachers and critical thinking assessment specialists from several disciplines as it is described in the conference proceedings of the American Philosophical Association (APA) widely known as "The Delphi Report" (Facione, 1990a: 12). Based on the APA Delphi consensus conceptualization of critical thinking a series of psychometrical instruments were created among which was the "Test of Everyday Reasoning (TER)" that was used in our research. The Delphi conceptualization was reaffirmed by independent research in the 1993/1994 national survey of employers, educators and policy makers, a replication study conducted by the National Center for Higher Education Teaching, Learning and Assessment (Jones et al., 1995).
Description and Scales of TER
The Test of Everyday Reasoning (Facione, 2001) is a 35 multiple-choice item test designed to measure reasoning and critical thinking skills. The items of TER are multiple choice questions designed to be scored dichotomously (2) with one correct answer and three or four distractors which represent frequently made errors or are designed to attract the attention of those who exhibit what are known as dispositional failures in reasoning (Engel, 1999). TER is suitable for persons in late childhood, adolescent and adult populations because the only background knowledge that is assumed is readily achievable through normal maturation and elementary schooling.
TER provides six scores for each individual: (a) an Overall Score which represents the number of the items answered correctly, indicating the overall ability of critical thinking, (b) three sub-scales: (i) "Analysis", (ii) "Evaluation", (iii) "Inference", and finally (c) two sub-scales which follow a more traditional conceptualization for critical thinking and reasoning skills: (i) "Deductive Reasoning", and (ii) "Inductive Reasoning" (Facione, 2001: 11-12, 25). …