In addition the PBC provides indirect allocations to colleges through its support of research funds in external research funding bodies. The block grants include a teaching component and a research component, but the research component applies only to universities. While the PBC establishes the enrolment levels at each institution for the purpose of allocations, institutions can enrol students outside these limits on a tuition fee basis within limits established by the PBC. The principal incentive for the colleges is negative: their exclusion from research funding.