"This article uses an economics perspective to examine the strength of the evidence on task shifting, to identify gaps in the evidence, and to propose a research agenda. The article is organized as follows: the introductory section continues by describing an economic-based conceptual framework to analyze skill mix policies; the second section describes the methods and data used to select studies to include in the literature review; section three summarizes the studies' results; and section four proposes a research agenda." (excerpt from abstract)