What is scientific literacy?
Scientific literacy describes the ability:

• to apply scientific knowledge in order to recognise problems, to acquire new knowledge, to describe scientific phenomena, and to make evidence-based conclusions,
• to understand the characteristic features of science as a form of human knowledge and enquiry,
• to recognise and to be aware of how science and technology shape our material, intellectual and cultural environment,
and the willingness
• to engage in science-related issues and to deal with them as a reflective citizen

(PISA Consortium Germany (2007): PISA 2006 - the results of the third international comparative study, p. 65) (Publication only available in German. PISA 2006 - Die Ergebnisse der dritten internationalen Vergleichsstudie)

This conception of scientific literacy is reflected in a theoretical competency model. It conceives of the important constructs as a sort of sequence:

In a certain situation, one encounters a scientific problem or question. In order to solve or answer this, various competencies are called for. The framework differentiates between three sub-competencies:

• recognising and formulating the problem which is to be examined and answered in a scientific way,
• describing and explaining scientific phenomena, and
• interpreting scientific evidence.

The basis of these competencies is a certain body of knowledge; hereby, the more object-related knowledge of science is distinguished from (meta)knowledge about science.

Alongside knowledge, motivational orientations or attitudes play an important role in dealing with the situation. Here, the conception focuses on three aspects, namely the interest in science, the support for scientific enquiry, and the responsibility towards natural resources and the environment.

Sample items can be found here.