Increasing impact in a time of decreasing budgets.

This virtual issue (VI) has been compiled to mark the CILIP Health Libraries Group Conference 2012. In line with the conference theme: 'Health libraries under the microscope: perfecting your formula', the VI is a collection of 10 articles and regular features that have been published in Health Information and Libraries Journal in the last 2 years. The VI focuses specifically on the topics of impact, value and cost-effectiveness. All the articles and regular features contained in this VI are freely available online.