Determining what counts as a construction is a major bone of contention between redundant and non-redundant construction grammar taxinomies. Non-redundant taxonomic construction-grammar models posit that only maximally productive patterns qualify as constructions because they license an infinity of expressions. Redundant models claim that, despite subregularities and exceptions, partially productive patterns also count as constructions. I demonstrate that even patterns that are not fully productive at the most schematic level often have subregularities that are. I assess the productivity of a multiple-slot construction in the British National Corpus (XML edition): it BE ADJ to V INF that. The assessment involves hapax-based productivity measures, vocabulary growth curves, and LNRE models. I show that although the productivity of it BE A to V INF that is limited at its most schematic level, some partially filled subschemas such as it BE hard/important/easy/difficult/possible /necessary/reasonable/impossible to V that and it BE ADJ to think/say/suggest/know/assume /realize/see that are arguably productive.