An investment decision can generally be described as a contingent decision relying on information gatherings from a previous decision or decisions made concerning the investment at hand. It is thus like the same investment decision is made over and over again. The difficulty in applying this tactic in human resource decisions is that the decision is trans-formed over time into another type of investment decision with other properties than the original one. Reasons for this could be that conditions for the investment decision have changed. This book analyses empirically how well models for decision-making under uncertainty can describe investments in human recourses. The two approaches focused on in this book are traditional decision analysis and real option analysis.