The paper focuses on a phenomenon of free word order through the analysis by reduction. It exploits its formal background and data types and studies the word order freedom of a (natural) language.
We propose and discuss several variants of a measure based on a number of word order shifts (i.e., word order changes preserving syntactic correctness, individual word forms, their morphological characteristics and their surface dependency relations). Such measure helps to understand the difference between word order complexity (how difficult it is to parse sentences with more complex word order) and word order freedom (to which extent it is possible to change the word order without causing a change of individual word forms, their morphological characteristics and/or their surface dependency relations).