Global economy

The Minimalist Program proposes five global economy conditions: Last Resort, the Minimal Link Condition, Fewest Steps, Procrastinate and Greed. These conditions compare possible (equivalent) derivations made from the same numeration ; the derivation which optimally obeys these conditions is the 'cheapest'. Only the cheapest derivation yields a grammatical sentence. Global economy conditions compare sets of derivations: they differ from local economy conditions in that local conditions are evaluated at every step in the derivation.

Example
A global version of the Minimal Link Condition (MLC) would compare the following two derivations:

(i) I wonder who1 t1 saw what (ii) I wonder what1 who saw t1

It will rule out (ii), because the link between the wh-element and its trace is longer in (ii) than in (i). Local evaluation of the MLC will take place at the point where the embedded C is inserted:

(iii) C who saw what

The local version of the MLC will rule out the derivation with movement of what right at this point in the derivation; this means that (ii) cannot be derived. Since local evaluation rules out uneconomical steps during the derivation, local economy reduces computational complexity. Considerations of psychological reality and conceptual simplicity have led to the idea that local economy is to be preferred over global economy.

Link
Utrecht Lexicon of Linguistics