Table 1.

Sentence complexity metric abbreviations and methods.

Complexity metric abbreviation	Specifics of implementation
Mx-T	The maximum level of the CCG derivation is listed.
Pr-T	Levels of all steps in the CCG derivation are listed.
Sum-T	The sum of all levels in the CCG derivation is listed.
Mx-I	The maximum of all integration costs for the sentence is listed.
Mx-S	The maximum of all storage costs for the sentence is listed.
Mx-C	Storage and integration costs are summed at each word in the sentence. The maximum of these sums is then listed.
Pr-I	The list of integration costs is used unchanged.
Pr-S	The list of storage costs is used unchanged.
Pr-C	Integration and storage costs are summed at each word as for Mx-C. The list of sums is then used.
Sum-I	The sum of all integration costs.
Sum-S	The sum of all storage costs.
Sum-C	The grand total of all integration and storage costs is used.

The list of numbers returned by each metric was fed to Eq. 1 as the list “L.”

CCG, combinatory categorial grammar.