With change our only constant, information systems researchers appreciate the need to measure and understand change processes occurring in software systems (i.e., software volatility). In this study we define a system-level multi-dimensional measure of software volatility. This measure can be used both quantitatively and qualitatively to analyze system behavior. We describe the lifecycle volatility of three application systems. We also discuss use of software volatility as a qualitative measure to interpret system behavior for software portfolio management.