1. INTRODUCTION

2. DATA AND MEASUREMENTS
2.1. The MOSDEF Survey
2.2. Line Luminosities and Nebular Dust Correction
2.3. SED Fitting and Stellar Dust Correction

3. INFERRING ξ_ion

4. ξ_ion DISTRIBUTION
4.1. Dust Attenuation Correction Uncertainties
4.2. Galaxy-to-galaxy Variations in Properties of Massive Star Populations

5. ξ_ion EVOLUTION WITH GALAXY PROPERTIES
5.1. ξ_ion and UV properties, implications for reionization
5.2. ξ_ion and ISM properties: O_32 and the BPT Diagram

6. COMPARISON WITH OTHER STUDIES

7. SUMMARY